Harrison Lake is an unincorporated community and census-designated place (CDP) in Bartholomew County, Indiana, United States. It is part of the Columbus, Indiana, metropolitan statistical area.

The community is in western Bartholomew County, built around two reservoirs on Denios Creek: North Harrison Lake and South Harrison Lake. A third reservoir, Tamerix Lake, lies to the south, outside the CDP. Columbus, the county seat, is 7 miles (11 km) to the east.

According to the United States Census Bureau, the CDP has a total area of 0.42 square miles (1.09 km), of which 0.27 square miles (0.70 km) are land and 0.16 square miles (0.41 km), or 36.97%, are water. Via Denios Creek, the Harrison Lakes drain southeast to the East Fork of the White River.