Falmouth is an unincorporated community and census-designated place (CDP) in Conoy Township, Lancaster County, Pennsylvania, United States.

[3][4] Falmouth is in the northwestern corner of Lancaster County, at the confluence of Conewago Creek with the Susquehanna River.

It is bordered to the northwest, across Conewago Creek, by Londonderry Township in Dauphin County.

Lancaster, the county seat, is 25 miles (40 km) southeast of Falmouth.

According to the U.S. Census Bureau, the Falmouth CDP has a total area of 1.0 square mile (2.6 km2), of which 0.4 acres (1,599 m2), or 0.06%, is water.