Renfrew is a small unincorporated village on the Connoquenessing Creek in Penn Township, Butler County, Pennsylvania, United States. It was founded by David A. Renfrew in 1882 on his farm. Once a thriving oil town, only the Methodist church is still active. The general store and the gas station have long been closed. In September 2004, Renfrew experienced massive flooding due to rainfall caused by the remnants of Hurricane Ivan. The Buffalo and Pittsburgh Railroad runs materials to and from the AK Steel mill in Butler through Renfrew along Railroad St. Once used by the Baltimore and Ohio Railroad, it was at one time a thriving railway that would travel down to Pittsburgh.