Lake Size: 1890 acres
Latitude: 39.91
Longitude: -85.99
Cities: Indianapolis
Lake Management: Indiana Department of Natural Resources

Information: Geist Reservoir is a reservoir in Indianapolis, Indiana, U.S., constructed in 1943 by damming Fall Creek to provide water for Indianapolis. Upon completion, Geist Reservoir was the second largest lake in Indiana providing approximately seven billion gallons of water. Geist Reservoir was named after Clarence Geist, a former owner of the Indianapolis Water Company who foresaw a deficit in Indianapolis's water supply, and envisioned Geist Reservoir to preemptively address the problem – but not without a casualty. Planning for the reservoir began as early as 1913, when hydraulic engineers estimated that White River and Fall Creek would not provide enough water for the increasing needs of Indianapolis. Geist gradually bought some 5,000 acres (20 km2) in Fall Creek Valley in the 1920s and 1930s, including the small town of Germantown, which today lies at the bottom of the reservoir. Although controversial, the reservoir was completed in 1943, five years after Clarence Geist's death. In the 1960s further controversy arose over plans for commercial and residential development in the area around the lake. A proposal in the 1970s to triple the size of the reservoir was defeated, and a housing boom began in the lake area. In recent years the Geist area has experienced rapid growth. The area is noted for its unique topography and the reservoir.