5. SimCity – Population 675,000
I once built a city using the Freedom map to see how many Sims I could attract to it. The Freedom map does not have any water, so of any map, you have the largest amount of land available to you in which to build a city. In theory, this would allow for the highest population imaginable (without using cheats or exploits).
Population 675,000 is where I hit a ceiling, but that is the biggest city I’ve ever built. I’m not sure how much higher you could go, but I wouldn’t be overly surprised if there was someone that’s been able to hit higher numbers.