Brandon Sanderson
Blast. I've got that in my records somewhere. It's been a while, now. Off the top of my head, I believe Luthadel was the biggest city with around two million. (Peter might have a better read on this.) I was shooting for 1920 London, but with a slightly better flow of food in because of the imperial structure an absolute monarch offers. It was the biggest city by a long shot, though. Others would have trouble topping 100k. Probably a 25%/75% split urban rural, weighted on rural, through the entire empire. Scope is relatively small. Smaller than the US. Bigger than Korea. If you email Peter@brandonsanderson.com, he might have the actual scale.
Brandon