Has New York always been the nation’s most populous city? November 22, 2011 by Pamela Landy · Filed Under: Statistics Yes, at least since 1800. At that time, Philadelphia and Baltimore were the second and third-largest cities. Census estimates for 1986 placed Los Angeles and Chicago, respectively, in those ranks. Related PostsWhich continent is the most populous?Who are the five Mafia families of New York City?Who first sighted the land that became New York City?How many women died in the Triangle Waist Company fire in New York City?For how long did New York City have a Miss Subways?