Johnstown is a city in Cambria County, Pennsylvania, United States, 43 miles (69 km) west-southwest of Altoona and 67 miles (108 km) east of Pittsburgh. The population was 20,978 at the 2010 census and estimated to be 20,402 in 2013. It is the principal city of the Johnstown, Pennsylvania, Metropolitan Statistical Area, which includes Cambria County.