The Gass House, also known as Gass Family Home, Farm House at Franklin Farms, and Union Plantation, is an historic home which is located in Guilford Township in Franklin County, Pennsylvania.

It has a two-story, two-bay-by-two-bay limestone extension on the north side, and is an example of Scotch-Irish farmhouse architecture.

[2] William Gass, a fuller who had immigrated from Ireland, built the house circa 1760, and left it to his brother Benjamin.

Patrick later became a soldier and a carpenter and was an important member of the Lewis and Clark Expedition.

Although Patrick was in line to inherit the house, it is unclear whether he ever lived in it as the owner.