In the late 1950s, Clairton High School (CHS) had a large student body, and the city had a "feeder" system of public and parochial elementary schools. The CHS student body was soon siphoned off, however, by new schools in Elizabeth Borough, Snowden Township, and Jefferson Borough. During the mid-1950s and into the 1960s, CHS was a Class AAA competitor in the formidable Western Pennsylvania Interscholastic Athletic League (WPIAL), playing against high schools in other mill towns up and down the Monongahela River Valley.