Nitpicking title: 'Town' vs. 'City', bugs me as a former CO resident. Ft. Collins is huge (~170k people compared to most CO towns which are 400-10k ppl). The title sort of leads you to believe it was a folksy, rural community effort. In reality Intel, AMD, Broadcom and a major State University are located there and that probably helped the effort substantially. https://en.wikipedia.org/wiki/Fort_Collins,_Colorado#Maj…
I looked into this, and Ft. Collins is a "Home Rule Municipality" under state law, meaning it can name itself either a town or city. It seems to have chosen to be a city, so you're right. Around the world, it seems that there's one consistent criterion for something being a city: it must have self-rule and a certain amount of government structure. Some places (notably not the US) have population requirements, but tho…
But that's the problem. It's not a "town" in a colloquial sense for anyone who grew up outside of major metro areas. If 170k is not enough, then there are no cities in Wyoming, Montana, North Dakota, nor South Dakota.