Unionville is a census-designated place[1] located in Center Township, Butler County, in the U.S. state of Pennsylvania.

[2] Unionville is located in the northwestern corner of Center Township and is bordered to the southwest by the Shanor-Northvue CDP, to the north by Clay Township and to the west by Franklin Township.

Pennsylvania Route 8 passes through the community, leading south 6 miles (10 km) to Butler, the county seat, and north 14 miles (23 km) to Harrisville.

It is in the Butler Area School District.

This Butler County, Pennsylvania state location article is a stub.