 East Prospect is located at (39.971506, -76.520601) and is situated on the west bank of the Susquehanna River opposite Washington Boro.The head end of the Amerindian-named Conejohela Valley (extends to the Chesapeake) and commercially developed dam-created Lake Clarke region are centered mid-river between the towns, and on a line, more or less from the two county capitals, York and Lancaster, which are also about equidistant.The borough is surrounded by Lower Windsor Township and is just west of the Susquehanna River.