I got 4. 1st, 2nd, 7th and 8th. I typed in 30 cities at least? I was quite unsure if it was of USA or of the world and what size of cities were considered. Ran out of time one letter short of the 4th city. I suppose I could've gotten the 3rd one as well after that. Maybe. :)
Cool quiz! I'd love a little more time, and I think it would be good to specify whether these are cities from all over the world or within a specific region.