East Pittsburgh is a borough in Allegheny County, Pennsylvania, United States, approximately 11 miles southeast of the confluence of the Monongahela and the Allegheny rivers at Pittsburgh. The population in 1900 stood at 2,883, and in 1910, at 5,615. As of the 2020 census, the borough population was 1,927, having fallen from 6,079 in 1940.