lorenzo-of-slytherin answered your question:
Casterly Rock compared to other cities (similar to the San Francisco picture) ?
...hmmm, I could possibly do that.... The Casterly Rock vs San Francisco comparison kind of happened because
I live near San Francisco and it's the big city I'm most familiar with, so that would be my go-to comparison
San Francisco is on a peninsula, bounded on water by 3 sides, so there's kinda a hard limit to how big the city can be, which is a similar issue with Casterly Rock. It's just that Casterly Rock is bounded by stone a lot more than water, but the hard limit is still the same.
Casterly Rock being approximately the same width as San Francisco was kind of something I found out by accident (see the first bullet point). I was looking on google maps, calculating distances in San Francisco. When I saw the distance from one side of SF to the other was about 2 leagues, I just sat there stunned for a minute, because I couldn't believe my eyes.
Was there any city in particular you had in mind for the comparison?
also, math-camel, @irrationalsense, punkrocknerdfighter, riana-one, and lizzierh, thank you so much for your suggestions on this post, I appreciate them and I will look into them!