South Fork is a borough in Cambria County, Pennsylvania, United States. It is part of the Johnstown, Pennsylvania Metropolitan Statistical Area. The population was 928 at the 2010 census, down from 1,138 at the 2000 census.
South Fork is located in south-central Cambria County at 40°21′54″N 78°47′26″W (40.365042, -78.790474), in the valley of the Little Conemaugh River at the confluence of its South Fork. U.S. Route 219, a four-lane expressway, passes just east of the borough and leads 10 miles (16 km) north to Ebensburg, the Cambria County seat. Johnstown is 10 miles (16 km) to the southwest, and Altoona is about 30 miles (48 km) to the northeast.
According to the United States Census Bureau, the borough of South Fork has a total area of 0.50 square miles (1.30 km2), of which 0.47 square miles (1.22 km2) is land and 0.027 square miles (0.07 km2), or 5.74%, is water.
As of the census of 2000, there were 1,138 people, 452 households, and 311 families residing in the borough. The population density was 2,208.1 people per square mile (845.0/km²). There were 484 housing units at an average density of 939.1 per square mile (359.4/km²). The racial makeup of the borough was 99.74% White, 0.09% African American, and 0.18% from two or more races.