Prospect is a borough in Butler County, Pennsylvania, United States. As of the 2010 census, the borough had a population of 1,169.

U.S. Route 422 (US 422) is a 271-mile-long (436 km) spur route of US 22 split into two segments in the U.S. states of Ohio and Pennsylvania. The western segment of US 422 runs from downtown Cleveland, Ohio, east to Ebensburg, Pennsylvania. The eastern segment, located entirely within Pennsylvania, runs from Hershey east to King of Prussia, near Philadelphia. US 422 Business serves as a business route into each of four towns along the way.