Strasburg Township is located in Lancaster County, PA and encompasses approximately 20 square miles and is bordered by West Lampeter and East Lampeter Township to the north, Pequea and Providence Township to the west, Paradise Township to the east, and Eden Township to the south.

According to the United States Census Bureau, the township has a total area of 20.0 square miles (51.9 sq km), of which 20.0 square miles (51.8 sq km) are land and 0.04 square miles (0.1 sq km), or 0.20%, are water. The township surrounds the borough of Strasburg, a separate municipality.

Strasburg Township lies entirely within the Pequea Creek Drainage Basin, which covers 148 square miles and drains the central portion of Lancaster County, flowing from the Welsh Mountains in a southerly direction.

At the 2020 census there were 4,457 people, 1,275 households, and 1,071 families living in the township.