Quote Originally Posted by Niall Mackay View Post
Interesting project!

Though, as a geographer, I can't let this uncommented:

There are no such things as "natural borders" (even if you call them barriers)!
For example, let's have a look at the Mississippi and other rivers in the MM-system: You used them as borders, not only between counties, even between states! Why?
Think about it: Do the left abutters of the river have more in common with the right abutters of the same river, or with some guys that live a two hours drive away from the river? Wouldn't projects like flood protections, harbour areas and the like be easier if there was only one authority in charge and not two competing and disputing ones?
Therefore, wouldn't watersheds make better borders?

Sorry about the rant, but the term "natural border" just annoys me.
I know, it's and old problem and still used in contemporary geopolitical work, but it's mostly crap. Rivers (and to a lesser extent, mountain ranges) may have some use as an international border if you aren't really at peace with your neighbour on the other side, but once inside a county, it turns into a problem.
While I agree on their being no natural borders (the very idea of a "border" is a human construct) I think you're being a bit harsh here. I read their post as they were using natural barriers as logical territorial end points. In this instance "barrier" isn't a euphemism for "border", it's exactly what it means; "barrier" - an impassable obstacle. Having a river or mountain range through the middle of a territory doesn't make any sense at all if you can't cross it, which is why historically they were frequently used as borders.

ETA... You also lump both mountain ranges and rivers into your rant, but then suggest that watersheds make better borders. Well watersheds are generally found in mountains...