This part of southern York County was claimed by both Maryland and Pennsylvania, and the boundary dispute was settled by the surveying of the Mason–Dixon Line in 1767.

Around 1812, a group of farmers set out to establish a town in south central Hopewell Township.

The earliest buildings were several houses, a workshop for making furniture and wheels, a store, and a tavern.

Anthony Stewart, owner of the workshop, served as the village clerk, and his shop became the main meeting place.

Through the efforts of Anthony Stewart, with the help of Judge Adam Ebaugh, the Post Office Department changed the town's postmark to "Stewartstown" on March 24, 1832.

[5] According to the United States Census Bureau, the borough has a total area of 0.8 square miles (2.1 km2), all land.