East Orange is a city in Essex County, New Jersey, United States. As of the 2010 United States Census the city's population was 64,270, reflecting a decline of 5,554 from the 69,824 counted in the 2000 Census, which had in turn declined by 3,728 from the 73,552 counted in the 1990 Census. The city was the state's 20th most-populous municipality in 2010, after having been the state's 14th most-populous municipality in 2000.East Orange was originally incorporated as a township by an act of the New Jersey Legislature on March 4, 1863, from portions of Orange town, and was reincorporated as a city on December 9, 1899, based on the results of a referendum held two days earlier.