 Upon completion, Geist Reservoir was the second-largest man-made lake in Indiana, providing approximately of water.The reservoir is located primarily in the northeast corner of Indianapolis and the southeast corner of Fishers, but small parts reach into the nearby towns of Lawrence, Fortville, and McCordsville.Geist Reservoir was named after Clarence H. Geist, a former owner of the Indianapolis Water Company, who foresaw a deficit in Indianapolis's water supply and envisioned the Geist Reservoir to preemptively address the problem.