New here with questions regarding size of continent!

[Justin Goldsmith]

I have recently started world building for a D&D game. The trouble that I'm running into is determining continent size, kingdom sizes and dispersion, population size and density. Any help in regards to this would be lovely. We are currently focusing on one continent at a time to flesh out, establish cities, towns, and villages. However, since I'm just beginning to get my feet wet it's a little overwhelming and assistance would be lovely.


Thanks!

[Chick]

There is a very useful source of information here: https://web.archive.org/web/20100825...john/demog.htm

By the way, welcome to the Guild! Will we get to see your map when it's finished?

[LordEntrails]

Very nice article Chick. I've already bookmarked it and will have to see how it compares to the generalizations I've used.

So, many years ago I did some reading on this topic. How accurate my memory is... well, who knows. But, here's how I start.

Excluding magic and divine intervention, in a middle-ages farming/technology level, about 97% of the adult population is engaged in making food as their primary task (farming, hunting, herding). An adult can cultivate upto about 10 acres (note, this is highly variable depending upon all sorts of things, but it gives you an idea). Meaning you need about 60 adults, or 15-20 families per square mile.

Villages are spaced and sized depending upon arable land, safety, and the desire to live close to your farmland (have far do you want to walk to work each day?) So, if it's safe enough, a village that farms in a 1 mile radius (about 3 square miles) would have about 180 adults (max).

Towns, (which are really where those 3% live and primarily serve as a marketplace) need to be no more than half a days travel from the farthest village. And realistically about a 1/4 days travel so that a farmer can get to the town, sell there goods, and get home in the same day. So, at "full" density, a town would be every 1/2 day travel, or about 15 miles in most fantasy worlds, with 30 miles be about the longest that could support a village. (That assumes the land is fully settled, no magic, etc).

So, what's the population of a town? Well.... IF (really big if) all the land is occupied as above, then a town supports villages in a 7.5 mile radius. A=pixR^2, or about 175 sq miles. 175 sq miles is farmed by 10,500 people. 3% of that is 315. Add the local 180 farmers and the town has 500 people. Not an enticing number in most cases. That's where magic, divinities and what not comes into play and you can make the towns whatever size you want (or you could just move more local farmers into the town).

To me, kingdom size is generally going to be driven more by politics and history more than by what is possible. What is that "possible" size? Mostly would be limited by the ability to communicate news, laws, orders, with some influence on troop travel times. With magic, their is no limit. Without? Depending upon the system of government, local governors or similar etc, say two weeks travel radius. Or about 420 miles from the governing force (assuming land, not sea).

How big for a continent? Well, earth has a 25k mile circumference. You could have a similar sized world with a single continent, or 100 land masses. So, this one really depends upon what you want. Any guidelines I can think of on this are... near random. How vast? How much open area? How many competing or allied kingdoms? How much does the sea play?

If you are worried about it, I suggest you actually start by creating a random world using one of the fractal terrain generators. Then pick a continent you like and pick a place of interest and put your starting kingdom there. You can detail everything else as inspiration hits and the party starts exploring.

[waldronate]

See also https://en.wikipedia.org/wiki/Central_place_theory (and the many other discussions of this and related market-area models).