Geist is an area in northeastern Indianapolis, Indiana (in Lawrence Township) and southeastern Hamilton County. It is named for Geist Reservoir. In 1943, the Indianapolis Water Company constructed Geist Reservoir in order to prevent a deficit in Indianapolis’s water supply. They believed that Fall Creek (Indiana) and the White River (Indiana) would not keep up with the demand for water in Indianapolis. In the 1970s, the company wanted to triple the size of the lake, but the plan was rejected in 1978 and homes began to spring up around the reservoir.