Mahaffey is a borough in Clearfield County, Pennsylvania, United States. The population was 368 at the 2010 census.
The community is served by U.S. Route 219.
The borough was founded by Robert Mahaffey in 1841, at a point where Chest Creek flows into the West Branch Susquehanna River.
First called "Franklin", the borough was incorporated in 1841. At the time it had a public school, four churches, a grist mill and a tannery.
Mahaffey was located at the junction of the New York Central & Hudson River Railroad and the Pennsylvania & Northwestern Railroad.
Mahaffey is located in southwestern Clearfield County at 40°52′33″N 78°43′41″W. U.S. Route 219 passes through the borough, leading northeast 11 miles (18 km) to Grampian and southwest 8 miles (13 km) to Burnside.
According to the United States Census Bureau, Mahaffey has a total area of 0.44 square miles (1.13 km2), of which 0.43 square miles (1.11 km2) is land and 0.008 square miles (0.02 km2), or 1.92%, is water.
As of the census of 2000, there were 402 people, 142 households, and 105 families residing in the borough. The population density was 1,085.5 people per square mile (419.5/km2). There were 157 housing units at an average density of 423.9 per square mile (163.8/km2).