Piscataway Creek is an 18.6 mi tributary of the Potomac River in Prince George's County, Maryland. The creek is a tidal arm of the Potomac for its final 2.5 mi, entering the Potomac at Fort Washington Park. Tinkers Creek is a tributary to Piscataway Creek, converging from the north 4.5 mi upstream of the mouth of the Piscataway. The United States Geological Survey records two variant names for Piscataway Creek: Pascattawaye Creek and Puscattuway Creeke. The Fort Washington Light was built to provide guidance for mariners entering Piscataway Creek from the Potomac River.