Fallowfield Township is an unincorporated community in Washington County, Pennsylvania, United States. It was the sixth township to be established after the 1781 formation of Washington County, and initially stretched from Elrama (north) to the Ten Mile Creek in what are, today, Union and East Bethlehem townships on the Monongahela River. Home to the John H. Nelson House, which was built circa 1895, this township was gradually downsized as various sections were sectioned off into new municipalities (Allen, Carroll, Pike Run, and Somerset townships and the borough of Charleroi). Now roughly 21.3 square miles in size, its population was 4,300, according to the 2010 U.S. Census.^[1]