Most Populated US Cities

List of Largest US Cities Ranked by population. Looking at how dense this cities are, we may also be in the running for most densely populated country in the world. It's no surprise that New York City tops the list. Anyone who's visited there knows how packed everything is from the skyscrapers to the people in Times Square. However, that's what makes it the vibrant city it is, and the other cities on this list are just as thriving and exciting, in their own special way. Source: U.S. Census Bureau (2007).