East Pittsburgh is a borough in Allegheny County, Pennsylvania, about 11 miles (18 km) 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 2010 census, the borough population was 1,822, having fallen from 6,079 in 1940. George Westinghouse erected large works there which supplied equipment to the great power plants at Niagara Falls and for the elevated and rapid-transit systems of New York.