City-Data is the place you want to go if you want information about a particular town or city in the United States. Not only does this site provide basic population and location information about the city of your choice but it also provides crime statistics, demographics, city government administrative budgets, average travel time to work, graphs of annual weather conditions, and photos of the city. I checked this out with 3 different cities, one with a population over one million, the second had a population around 60,000 and a small town with a population under 15,000. They all contained great info.
When loading the information on the city, don't be turned off when the Google ads pop up first with info about companies providing demographic information. The good stuff comes shortly after the ads and it is free.