How many people can 1 Acre of farmland feed / year?

[howandwhy99]

This is a split thread from here: Wilderlands hex size too small or just right?
(just in case anyone else wants to chime in)

howandwhy99
I've been using a 3 field system for my Greyhawk campaign, but by acre not square mile. 1 acre can feed 1 adult per year and all that. 61 acres in a square mile. I've had difficulty figuring out what ratios of urban populations can be supported by surrounding food supplies. I want to go with more than 10%, but I think that's awfully high by historical numbers. On the other hand, 50,000 people in a city I can believe, but 500,000 total in the while area outsizes any published campaign setting numbers I know.
--SNIP
I guess I'm looking for ideas on how much food can be grown by 1 farm family or manor house on a plowed field per year (including climate and seasons?). And how much that yields so other people have time enough to... do other things. 10% of a population not farming seemed very low for to allow for every other NPC class. And the populations are so large for a fantasy game where travel is slow and not much happens in civilized rural lands.

Starbeard
Partly it depends on what type of food is being grown, what farm methods are in use, and any number of other factors like climate, legal systems, trade routes, etc.

Since Russell's time it's been generally taken that medieval Europe averaged an 'urban index' of 5% (that is, 5% of a given region's population lived and worked in an urban setting). As towns became bigger the urban index didn't necessarily become bigger: the whole population just got bigger. As farming technologies advanced, the sustainable UI increased. However, Chaucerian England supposedly had a much lower UI (I think he figured something like 4-4.5%), with smaller cities and nobles who lived quite often in the countryside. Regions of northern and central Italy, by comparison, sometimes had a UI as high as 10%, because of cramped conditions, fertile fields, and a proliferation of high-traffic trade routes that connected the area to the rest of the world by land and sea. And then there might be laws that artificially force a population to become urbanized, like in Tokugawa Japan, where he estimated some regions to have as high as a 40% UI, which otherwise seems completely unsustainable.

Going with Japan, the farm unit was the chō, which is somewhere just shy of 3 acres. I can't remember exactly where I got the numbers, but in my notes for running L5R I looked up the rice yields per acre/chō in various places during the 18th-19th century (mostly Java and Japan), and then used the average nutritional information for rice to determine how many people could be fed at a subsistence level per chō of farmland. I rounded the ranges to something simple and playable, which was anywhere from 5-30 koku per year, averaging at 10-20 (koku = a theoretical measurement assumed to feed one man per year at a subsistence level). I guess that comes out to an average of 4-6 people fed per acre. Other grains often have lower yields, but then again they also might have different levels of technology for production, or the space to have larger fields per farmer.

There's also the added factor of hunting, fishing, gardening and foraging, which people would do for their own food and to sell. Honestly I have no idea how much that would contribute to the food requirements.

I'm sorry I can't provide anything more definite than that, or with any actual documentation. It was a long time ago I put these figures together for a kingmaker L5R game, and the notes I took have long since disappeared. I do remember reading a couple of different web pages on rice yields before mechanized farming, in Japan and Java in particular, and also reading through a number of J.C. Russell's books for figures.

[coffee]

I don't mean to be critical, but where do you get the 61 acres per square mile figure? Wikipedia reinforces what I learned when I was young, that there are 640 acres per square mile. (I know there are different sizes of acres out there, the they're roughly the same size.)

Hope that helps!

[howandwhy99]

Yeah I'm way off. I'll have to go back to my numbers to find out why that happened. Strange

[grodog]

Might be worth investigating Fief @ www222.pair.com/sjohn/fief.htm and the series Magical Medieval Society @ www.xrpshop.citymax.com/page/page/3906392.htm if you're interested in basing this on some solid historical research.

[aldarron]

Speaking as an archaeologist here, there is absolutely no possible answer to that question. First you have to ask what the subsistence base is (hay based agriculture, swidden based agriculture, grain based agriculture, tuber based agriculture, etc etc.) Then you have to ask what the technology being employed is. Then you have to as what the climate is. Then you have to ask what the elevation above sea level is. So on and so forth.

Now, probably you are looking for something equivalent to the low countries of medieval Europe, with a grain (wheat) subsistence base, supplemented with dairy and sheep farming. For that I'd recommend looking at Adventurer Conqueror King, where these things are worked out in detail as relates to the standard D&D gold piece.

ACKS Economics

[Deleted]

As my main interest is in the ancient/roman period, did the UI percentage go up or down from, say 100-200 AD to 1400 AD? Either in France/Gaul or Britannia?

[dragondaddy]

Oct 22, 2015 12:13:17 GMT -6 @hedgehobbit said:

As my main interest is in the ancient/roman period, did the UI percentage go up or down from, say 100-200 AD to 1400 AD? Either in France/Gaul or Britannia?

A person needs about 15 Bushels of grain a year to live healthy...

This discussion comes up about every four to five years on a regular basis. I can always tell which scientists and archaeologists (not talking about you Aldarron, just all the scientific journal quacks with suck papers I had to read to learn all of this...) are the jackasses (and there are a lot of them!) and they don't know what they are talking about if they don't include any actual measurements of crop yields in their wordy scientific dissertations, a few of which will be provided here for reference. Most of the references you'll find very useful here however...

The short answer... Yields went up during Roman times, then dropped dramatically during the Dark Ages bottoming out in Medieval times then surging during the Rennaissance due to new farming methods, plagues which decreased the pressure on arable lands and new technology.


3600 B.C.
Crop yields for grain (Wheat) back then was about 12-13 Bushels peracre with a maximum of 22 Bushels an Acre. Barley yields were slightly better maybe 24-26 Bushels an Acre. A Bushel will get you 60 pounds of wheat, and the average consumption of one adult in the middle ages was about 3 lbs a day of grain. So one acre of wheat under cultivation would provide 3lbs of bread or cereal a day for one adult for about 440 days or about a year and three months. So 1 acre under the best conditions will feed 1-1/3 to 2 people and under average conditions it takes about 2 acres to feed one person... however this varies considerably;

Roman Era
Crop yields in the Roman Era was were based on a unit of land measurement known as an Iugera. One iugerum was a plot of land about 120 feet by x 240 feet. One iugerum was equal to about 0.65 acres or a quarter of a hectare...small farms had 18-108 Iugera (Early Republic), Medium farms were 80 to 500 iugera and large farms (Late Empire) often exceeded 1,000 iugera. A family of 6 needed 12 Iugera to survive at a subsistence level and 20 iugera with livesstock. (A note here: Livestock tripled the cultivation rate so having plow cattle meant the family could plow about 60 iugera during the planting season.

Back to more modern measurements, the Butser Roman farm in the Southern United Kingdom currently yields 26-30 Bushels of wheat per Acre, with an average of about 28 Bushels and acre. In the mild climate of Mediterranean Rome they practiced crop rotation and grew three crops a year starting with grain like wheat or barley, then a legume or bean crop, and finishing with an Emmer or Einkorn wheat crop. Yields went down over time as arable land was over exploited. A major reason for the Roman conquests, because every Roman citizen was entitled to free grain. (Yes, the Romans setup one of the first welfare states!). As the Roman Empire grew, so did the need for slaves and good farmland to supply the bread to the masses!

Medieval Times
Yields in Medieval times in Europe were simply terrible, from the Domesday survey conducted in 1086 A.D.
Rye = 7 Bushels an Acre
Wheat = 5 Bushels an Acre

Some farmers did get yields of 10 bushels an acre, and that was considered great!

Modern Yields
Compare with today. Here in Indiana down the road, the average yield for corn and wheat is as follows:
Winter Wheat = 76 Bushels an Acre
Spring Wheat = 67.6 Bushels an acre with maximums to 130 Bu/Acre for the genetic stuff.
Corn (all Purpose) = 188 Bushels an Acre


USDA Crop Yields 2014:
www.usda.gov/nass/PUBS/TODAYRPT/cropan15.pdf

Domesday Survey Yields (1086 A.D.):
www.ibiblio.org/london/agriculture/general/1/msg00070.html


Butser Roman Farm Research (experiemental Farm Yields):
books.google.com/books?id=hBNr765THaIC&pg=PA211&lpg=PA211&dq=butser+experimental+farm+yields&source=bl&ots=yaz46NBKtb&sig=1bp2wC89xruWWOBMKC2dFAff_5I&hl=en&sa=X&ved=0CCMQ6AEwAWoVChMI5IWbp6fcyAIVRuYmCh252QM5#v=onepage&q=butser%20experimental%20farm%20yields&f=false

and
www.butserancientfarm.co.uk/

Crop Yields of Prehistoric Cereal:
www.butser.org.uk/cereal%20yields.pdf

Fallowing, Crop Rotation, and Crop Yields in Roman Times (400 BC-400 A.D.):
www.jstor.org/stable/3741455?seq=1#page_thumbnails_tab_contents


Our discussions about this in 2001 in Rec.Games.Frp.DnD Usenet Group (3600 B.C. Crop Research):
groups.google.com/forum/#!searchin/rec.games.frp.dnd/agriculture$20and$20/rec.games.frp.dnd/vdtQZu_itRE/_Ebw6ABRh_sJ

How Big is a City-State Anyways? (2005);
groups.google.com/forum/#!topic/rec.games.frp.dnd/yhs9bahDkVA[1-25]

Roman Era Agriculture Reference:
en.wikipedia.org/wiki/Roman_agriculture

Roman Agriculture (Geoffrey Kron Paper):
www.academia.edu/436589/Roman_Agriculture


Measurement Reference:
1 Bushel = 60 pounds (lb)
Hectare to Acre Conversion Rates 1 acre = 2.47 Hectares
iugerum to Acre Conversion rates .65 acre = 1 iugera
640 acres = 1 square mile.
100 hectares = 1 square kilometer.

[dragondaddy]

I'm such a geek. I wanted to crunch some more numbers to get a baseline on how modern farmers are doing, economically speeking, so did some more research. Now I know why so many farmers are growing corn here, and here's what I came up with;

Indiana Farm Calculations
160 Acres under cultivation
5 Acres living space

Prices October 2015
Corn (maize) / Bushel 4.3775
Wheat 4.585
Winter Wheat 4.346

Conversion Factors
Barley (48 lb/bu)
1 bushel = .021772 metric ton
1 metric ton = 45.9296 bushels
CORN & SORGHUM (56 lb/bu)
1 bushel = .0254 metric ton
1 metric ton = 39.368 bushels
WHEAT & SOYBEANS (60 lb/bu)
1 bushel = .0272155 metric ton
1 metric ton = 36.7437 bushels
Note on Tons:
British Tonne or Long Ton = 2240 lbs.
American or Short Ton = 2000 lbs.
Metric Ton = 1000 kg, approximately 2204 lbs.

Yields (Indiana)
Winter Wheat = 76 Bushels an Acre
Spring Wheat = 67.6 Bushels an acre with maximums to 130 Bu/Acre for the genetic stuff.
All Wheat = 43.7 Bushels per Acre
Corn (all Purpose) = 188 Bushels an Acre

160 Acre farm gross profit (2014 annual)

Winter Wheat 160*76*4.346 = $52,847.36
Spring Wheat 160*67.6*4.585 = $49,591.36
All Wheat (avg) 160*43.7*4.585 = $32,058.32

Corn = 160*188*4.3775 = $131,675.2
Corn Gross Income per Acre = $822.97

Corn following corn (Costs to Farm per Acre in 2014)
Preharvest machinery
Fixed $ 22.70
Variable $ 24.00
======================================
Seed, Chemical, etc.
Seed (35,000) $134.90
Nitrogen@$.47/lb (186) $87.42
Phosphate@$.48/lb (69) $33.12
Potash@$.41/lb (56) $ 22.96
Lime (yearly cost) $ 10.00
Herbicide $ 35.50
Insecticide $ 23.00
Crop Insurance $ 14.60
Miscellaneous $ 11.00
Interest on Preharvest $ 13.22(8 months at 5%)
Total: $432.42
======================================
Harvest Machinery
Combine $ 10.90
Grain Cart $ 3.20
Haul $ 7.06
Dry (LP Gas@$1.60/gallon) $ 35.52
Handle (Auger) $ 4.06
Total: $ 60.74
=====================================
Labor
2.85 hours @ 13.00 $37.05

Total Cost Per Acre $ $530.21
Net Profit / acre $ 292.76
Net Profit Annual $46,841.60

Billy Fox from British Columbia listed the following farming expenses per acre in 2014 annual Canadian Dollars. Most likely crop... Winter Wheat.

Canadian/US Exchange Rate 1 Canadian Dollar = .76 US Dollars

Winter Wheat Gross Profit per acre (2014) $330.30

Planting $ 30
Fertilizer $ 77.60
Seed $ 83.00
Pesticide $ 17.00
Herbicide $ 5.76
Total: $ 213.36
Converted to US Dollars: $ 162.15
+ Harvest Costs $ 97.79

Total Costs $ 259.94
160 Acre Canadian Farm (Wheat) 2014 Net Profit : $11,257.60 (US) or $14,860.03 Canadian

Reference: talk.newagtalk.com/forums/thread-view.asp?tid=524064&DisplayType=flat&setCookie=1

US Farm Costs Reference:
reference Iowa Crop Production Costs 2015:
www.extension.iastate.edu/agdm/crops/pdf/a1-20.pdf

[howandwhy99]

How many people does it take to farm 1 acre of land?

I understand this is going to vary according to the soil, crop, individual, etc. But I had understood 1 person can farm 1 acre per year and feed 1 person from it. So a lot of early civilizations still required supplemental food sources like hunting and gathering.

Thanks for all the replies so far. This is good information.

[tetramorph]

Oct 25, 2015 13:03:40 GMT -6 howandwhy99 said:

How many people does it take to farm 1 acre of land?

I understand this is going to vary according to the soil, crop, individual, etc. But I had understood 1 person can farm 1 acre per year and feed 1 person from it. So a lot of early civilizations still required supplemental food sources like hunting and gathering.

Thanks for all the replies so far. This is good information.

Again, I am sure this will vary by region and era.

But if I understand correctly, the British acre names the area a team of oxen can plow in one day.

So my guess is that a modern acre is probably related to that description about as well as a foot is related to my actual shoe size. You get the point, but it isn't identical.

[tetramorph]

howandwhy99, here is a website I have used and found helpful in building my campaign(s):

www222.pair.com/sjohn/blueroom/demog.htm

[Deleted]

dragondaddy that is great collections of some sweet links and I like the modern info you provided also.

[oldkat]

Fascinating thread; as someone said, the topic cycles on the forums.

Personally, I have no desire to micro-manage my own campaign (if it ever gets going) down to this kind of detail.

1. Time lost can't be regained; rather spend it on something else.
2. Will it ever, really, come into play? or affect the players? If not, I'm out the door.
3. Table crunching is best left to the youngsters--my eyes can't take all that anymore.
4. I'm sure Rob K. has a whole chapter on this subject in his (I hope) soon to be available, book.

[oldkat]

If one happens to have a copy of the Judges Guild campaign booklets (Wilderlands of High Fantasy, for example) p.30 (of said booklet) describes this situation very well under the heading-- Population Density.

[delta]

Pitching in here: When I've researched this in the past, I've hung my hat on Gies, Life in a Medieval Village, Ch. 2. It says there that official tax records were counted in "virgates", a unit of land to support one family; and "hides", of 6 virgates each. Units are variable: noted in multiple locations that the hide is usually 120 acres (so: virgate 20 acres), but in Elton 1279 the virgate was 24 acres (so hide 144 acres?). Assumption seems to be average family size of about 6 people. So put that together and you get about 3-4 acres of arable land per person (although accounted in virgates/hides in practice).

[robertsconley]

Hides and Virgate were variable because they were based on land quality as measured by how they produced. A 1 hide farm in the rocky highlands will be larger than a 1 hide farm in the Thames river valley.

The best gaming reference for this that lays out the numbers is Axioms #3 from Autarch.
www.drivethrurpg.com/product/194008/Axioms-Issue-3

The best supplement that makes a nice mini-game out of managing a manor is Columbia Games Harnmanor. It about as complex as managing starships in classic Traveller.
columbiagames.com/cgi-bin/query/cfg/zoom.cfg?product_id=4751

In Axioms Alexander Macris lays out his assumptions.

The economy of is built from a small number of assumptions, the most crucial of which are
(1) that an unskilled laborer earns around 1sp per day of work;
(2) that a typical farm yields one quarter of grain per acre;
(3) that one quarter of grain sells for 4gp; and
(4) that risky investments will yield a rate of return of 3% per month.

One quarter of grain is 8 bushels of grain or 480 lbs of grain (60 lbs per).

The nice thing about this you can alter the assumption and work through the math to come up with your own figures. As for simulating the different sizes of virgates and hides just have a land quality factor like Harn. A LQ of 1 means that 1 acre will produce one quarter of grain. A LQ of 1.5 means that one and half (12 bushels) of grain will be be produced and conversely a LQ of .5 means only 1/2 quarter or 4 bushels will be produced.

[rustic313]

This academic paper has a wealth of data:
citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.562.1552&rep=rep1&type=pdf

ENGLISH AGRICULTURAL OUTPUT 1250–1450: SOME
PRELIMINARY ESTIMATES

Stephen Broadberry, University of Warwick
27 November 2008

Here are some nice summary order of magtiude estimates for England in the late 14th century (around 1380).  I like using post-Black Plague England as I think it reflects our game setting a bit better -- a land sparsely populated, with many abandoned ruins, ghost towns, and the borderlands creeping in as man's age seems to fade.

Population:  2.37M Total, 1.79M of which are rural (75% rural, or three farmers for every urbanite)
GDP:  2.71L million (table 18)
    % of GDP that goes to workers:  60%
    Rest of GDP:  11% Taxes & Tithes, 11% Capital Costs (upkeep/MX), 18% Rents --> Rounded Off, this is:  Tax & Tithe 1/10, Upkeep 1/10, Rents 2/10, Wages 6/10.  Note that pre-black death, the share for workers is about one tenth less, with more wealth going to the taxes and tithe (as upkeep seems fairly fixed).
Acres Under Cultivation:  4.76 million acres sown, 3.22 mil acres fallow but arable; the paper notes that the max arable land in England is about 10M acres; England has 60M acres so that's about 1/6 of total land being possible
Horses (Figure 8):  4 horses per 100 acres of demesne land, so maximum of 47.6K horses across England (likely less, non-demesne land probably had half to 3/4 this number)
    Types:  1/5 horses are "non-farm" (i.e. riding or war horses I'd assume).  Table 11
Oxen:  About 5, but could be as much as double the number of horses (Table 5)

Calories per day for human consumption:  1715 + animal products (milk, meat, etc) -- still lean rations, but remember this is an average across 2 parents and 2.5 children; also its way up from the pre-black death days
Cows:  1.3M, about 1/3 each milk, beef and young (Table 7)
Sheep:  14.67M -- six for every man, woman and child!
Pigs:  390K

-----------------------------------------------

A VILLAGE
With all those figures in mind, let's scale it down to a D&D village of, say 300 people, which we'll call Pomlett.  In the analysis that follows, I'll use the cash conversion used by OED, which is 1 shilling = 3 SP, but you can convert as you see fit.

Pomlett is a pastoral village of 300 souls ruled by a 4th level Fighter, and assisted by a pair of level 3 characters (perhaps a Level 3 squire and a Level 3 Cleric).  It consists of about a dozen hides, each hide having 25 people (four families with a husband, wife, and 2.5 children plus a few drifters and elderly folk).  

There are about 600 acres under cultivation, with another 226 laying fallow.  The fields make up just over a square mile.  There are about 20 horses in the village, four of which are war horses (for the Hero and his two third level assistants).  There are about two or three dozen oxen.  The town has an average herd of cattle (165 head), about 50 pigs, and about 1900 sheep.  Most peasant families have a few sheep, and the wealthier peasants have a few head of cattle.  The village is surrounded by about 6square miles of land that is not arable (rocky, woods, etc).

A two-league hex could fit about three of these villages, maybe four.

ECONOMY
The total economic output of the village is about 300L per year (343L to be precise, but I'm rounding down because the nearby Free Town is more prosperous and has a greater concentration of wealth.  City Slickers and their Guilds...).  Of that, 180L is retained by the peasants.  That means each peasant family can count on about 3.75L each year, or about 6 shillings per month (18 SP).  That means each family is living on a daily wage of 2.4 pence, which is exactly what an unskilled thatcher's mate earns in 1380.*  Most peasant families supplement these meager cash earnings with their subsistence agriculture, small animals, or odd jobs for the local Lord.  

The other 120L is divided as follows:
- 30L (1800 SP) for capital costs.  Mostly upkeep for buildings, repairs for the mill, etc.
- 60L (3600 SP) for rents.  Most of these are payable to the local lord (said Hero), with some for the Baron.  The baron ends up taking a larger slice of this (from the lord) in the form of feudal rights, revenues of justice, and a few other feudal tricks.
- 30L (1800 SP) for taxes and tithes.  The Baron claims about 10L (600 SP) in taxes, leaving 20L for tithes (1200 SP - not quite 10%).  Before the Death, the church and baron claimed more, but since the Plague the fewer peasants that remain have demanded a better standard of living.

MILITARY FORCES
The village can field three "lances:"  The F4, F3, and C3 (or another F3) each atop a warhorse, with the F4 having a spare warhorse.  A typical lance looks like this:
F4 (with warhorse), F2 bodyman (armored, atop a draft horse), 2xF1 (heavy foot, walking, or perhaps with ponies), 1d6xF0 (light foot, crossbowmen, or pikes).

In addition to the three lances, a F2 commands the village's "Trained Band" which consists of 2xF1 and 8xF0, organied as med foot, crossbowmen, or pikes.  All told there are about 40 HD under arms.  As feudal subjects, the F4 and villagers owe service to the Baron and thus are liable to be called up for guard duty or even to go on campaign.  Assuming they owe 40 days of service, one of the lances or the trained band can be found guarding the Baron's castle for about half the year, with the others tending to matters in the village itself.

In times of emergency, another 30 men (the "alarm lists") can be fielded (light foot).  In great emergency, by arming the very old, the very young, and the women-folk, perhaps another 30 could be fielded.

------------------------------------------------------------------------------

If you recall from OD&D, the Baron claims ten coins per resident (we'll use SP as OED is on a Silver Standard).  That would be 3000 SP for a village of 300.  These numbers clearly are in the ballpark.

To get to 3K SP, one can first use the 600 SP for taxes.  The Baron would then have to claim 2400 SP of the "rents."  Notably, "support and upkeep" for a Hero is 80 SP (1% of 8K XP); for the two third level folks is another 80 SP; for the four 2nd level types its 80 SP.  That's 240 SP...  Over 12 months, right around 2400 SP (of course, they all pay their support and upkeep on time, and the Lord cuts them a break for Christmas and Mid-Summer).  So basically the Baron can extract the rest of his 2400 SP from the leveller-types in the village in the guise of support and upkeep (feudal rights, revenues of justice, direct rents, etc).

That leaves 800 SP from the "rents" for the Hero and other local elites to support themselves in some style and maintain a small manor house.  The local lord is also likely skimming off the capital upkeep costs, by doing things like steering business to maintain buildings to favored relatives, peasants, etc.  If you recall the average peasant family is living on 18 SP per month, having 60-70 SP to throw around is pretty decent for a Hero.  The Cleric 3 is using a slice of the 1200 SP in tithes to maintain the parish church, etc as well. 



medieval.ucdavis.edu/120D/Money.html

[rustic313]

Today I was looking at my Outdoor Survival map and noticed another interesting factoid related to this.


OUTDOOR SURVIVAL MAP RATIOS MATCH JUST ABOUT PERFECTLY
For every town, there are about 2.5 strongholds. That is, assuming that each of them have equal populations, about 7/10 of the population is rural and 3/10 is urban. This matches quite well with our real-world data on medieval England as a first order approximation if we assume that everyone in a stronghold is rural, and everyone in a town is urban.



MORE DETAILED EXTRAPOLATION FROM OS
It also lets us approximate the size of these towns if we want to do a little more thinking.



Average Stronghold = 5 villages (2-8) of 250 people (100-400) each = 1250 people

Thus each stronghold can support 416 urban eaters (1250 / 3) per our real world academic data.



Assume that 5% of the inhabitants of the rural stronghold are engaged in non-agricultural tasks: quarrying stone, mining iron ore, working as smithies, etc: 60 people. Most of the castles also have about 30 HD of monstrous occupants. Thus the stronghold can support about ~325 urbanites in another location. The castle guards are assumed to be part-time agricultural workers and vassals and thus don't count as "eaters," but any additional castle occupants or mercenaries would come out of that "eaters supported" figure.



With 2.5 strongholds per town, that means that the town should have about ~800 people.




The other implication here is that each town should have a web of trading relationships with 2-4 of the nearby strongholds.

This is also quite consistent with the historical record.  A quick Wiki search (https://en.wikipedia.org/wiki/List_of_towns_and_cities_in_England_by_historical_population#Medieval_England) shows that <20 towns in 14th century England had populations over 2000.  Only four towns exceed 4000.  The vast majority of urban settlements are around 1K people.


BUT I WANT BIGGER CITIES!
Your fantasy setting may require some bigger cities than the relatively small, grim towns of ~1K the above math demonstrates.  There are a few plausible ways to do that.

Local Farming (+300 urban residents):  You might assume that the town is surrounded by 2-8 villages of 100-400 farmers as well.  This would add another ~300 urbanites.

Larger Rural Strongholds (+300 urban residents): You could assume that NPC strongholds are longer established, and thus have 8 villages of 400 residents.  That would nearly double the size of the nearby towns.

Trading with "Lair" Occupants (+300 to 600 urban residents):  One could assume that some trading occurs with the nomads, bandits, demihumans, and other "wilderness encounters" that occupy lairs in the countryside but don't have formal strongholds. That could bring strongholds up to a somewhat larger size.  As a random guess, it seems reasonable to allow all of the Lairs within a 8 hex radius to count as another stronghold.  Within those ~48 hexes, it seems plausible that there are at least 4 neutral/friendly encounters that might be willing to trade food, adding another ~300-600 urbanites.

The plot implication here is that urban authorities might be displeased with PCs that "clear" certain wilderness monsters away.  That orc tribe might occasionally harass merchant caravans, but they may also be selling food to the urban center via a guild...

Grain Imports (2x to 4x population, or +300 per large merchant): If you allow that towns might have access to "off the map" food supplies (grain imported via sea lines of communication or rivers was a Big Deal in parts of the ancient world, and indeed our OS map has five towns clustered around the central river) then that could allow larger settlements. 300 people need about 30-60 tons of grain to feed for a year, which is one ancient merchant ship of decent size. So if there's a steady flow of goods coming into the town then theoretically quite large urban populations can be supported. As an ancient world example, research has estimated that Athens supported 1/2 to 3/4 of its population via imports from the sea*. In our setting's scale, if we assume that a city of 1400 people is doubled due to imports, we get a population of nearly 3K, which would be one of the largest cities in 14th century England.  This city would need about half a dozen large merchant ships each year to keep it fed in addition to local sources.
*https://www.princeton.edu/~pswpc/pdfs/krotscheck/010603.pdf

There are significant plot/world-building implications to this justification.  Historically, cities that were dependent on sea lines of communication for imports raised significant naval forces and had major town walls to defend from land-based attack.  They jealously defended those SLOCs and had distant colonies/strongholds planted in strategic locations to control choke points on the SLOCs.  For example, Athens was very concerned about securing the flow of grain through the Hellespont and had colonies in Thrace.  These cities also were prone to launching foreign expeditions to secure more grain sources -- Athens invaded Egypt and Sicily.  Think of grain sources as the modern day equivalent to crude oil and the plot-politics emerge quickly.  Any threat to the grain supply lines will quickly raise attention -- this could require the services of heroes to secure the line (perhaps a Dragon or other monster has set up shop on the key river/ocean straits), cut the line (if hired by an enemy power to undermine the city), or just be a lucrative opportunity for selfish neutrals to do some privateering.

Fewer towns and more strongholds: One could design the map to have a different ratio of rural strongholds to urban towns.  Rather than 2.5 to 1, you could go with 4 or 5 to 1.  The outdoor survival map isn't the end-all be-all!

Magical Food Production (+X?):  One could assume that magic allows for greater food efficiencies and thus a larger urban population.  Or instead of magic, one could perhaps ascribe great agricultural production to the Elves, halflings, or some other source, making them the "breadbasket" of the known world.

[Red Baron]

There are 260 hectares per square mile and about 25 miles per 5 mile hex (those numbers arent exact). That gives 6500 hectares per hex.

A person eats about 1 tonne (1000 kilo) of food per year. This is an approximation ignoring dry weight vs water weight and variation in diet, nutritional density in food, etc.

Ancient - Mediaval agrocultural yields were typically 500 kg to 1 tonne per hectare. On natural non-industrial ag pastures, natural forage yield will support about 1-2 cows per hectare and it takes 2 years to raise a steer for slaughter giving 1 tonne of beef (minus losses).

That gives us 1 person per hectare for relatively good medieval agriculture or 1 person per 2 hectares for really bad ag or livestock production.

So a pastoral/ranching or poor agricultural hex can support about 3000 people while a rich agricultursl hex can support about 6000 people.

I would assume that small castles (30-180 guards) have far more land than people, and only look at city populations. If you put your cities on the coast, they can fish and import food meaning that you can ignore land area for cities too.