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. It was once a booming oil town with a general store, a school, a post office, a gas station, and a Methodist church. In September 2004, Renfrew experienced massive flooding due to rainfall caused by the remnants of Hurricane Ivan.