The Western Pennsylvania Professional Football Circuit was a loose association of American football clubs that operated from 1890 to approximately 1940. Originally amateur, professionalism was introduced to the circuit in 1892; cost pressures pushed the circuit to semi-professional status from about 1920 through the rest of its existence. Existing in some form for 48 years, it was one of the longest-lived paying football loops to operate outside the auspices of the National Football League.