East Fork Lake is situated off SR 222, two miles south of Batavia and 25 miles east of Cincinnati. Access to the north side of the lake is from Batavia-Williamsburg Road (old State Route 32). Access to the south side is from State Route 125. State Route 133 has access to East Fork Wildlife Area on the northeast side of the lake.
East Fork Lake (a.k.a. William H. Harsha Lake) is an impoundment of the East Fork of the Little Miami River and two small feeder creeks, Poplar and Cloverlick creeks. US Army Corps of Engineers maintains the dam at the west end of the lake, providing parking and fishing access to the tailwater area below the dam.
Water depth at the dam is normally 113 feet, making it the second deepest lake in Ohio. The shoreline of the lake is steep and rocky in most areas, falling off rapidly into deep water. Both large and small bays containing standing timber and brush are evident around the lake. The upper reaches of Cloverlick and Poplar creeks, along with the main stem, were left uncleared to provide fish habitat.
Six public boat ramps located around the lake: the Corps Ramp (at the dam), Tate (a.k.a Bantam), North Shore, Reisinger Road (a.k.a. Bethel), Tunnel Mill, and Campground Ramp (for camper boat access only).
East Fork State Park offers a modern campground, equestrian camping, cedar cabins, camper cabins, swimming beaches, picnic areas, shelter houses, horse riding trails, hiking and backpacking trails, and mountain bike trails. The lake is known for hosting rowing regattas; it has access designed for rowing sculls near the swimming beach.
- Check for water quality advisories
East Fork Lake was built to provide flood control in the East Fork and lower Little Miami River valleys; storage for water supply and water quality control; and recreation, including fishing and hunting. The lake was constructed by the U.S. Army Corps of Engineers and leased to the Ohio Department of Natural Resources. Construction of the dam began in July 1970 and a partial pool was impounded during the 1978 season. The lake was raised to normal pool of 1,971 acres in spring 1979, and has 32.3 miles of shoreline.
The earthen fill dam is 200 feet high and 1,450 feet long. Water release is controlled by a series of multi-level gates in the outlet structure, providing control of the water quality in the tailwater. The lake drains an area of 342 square miles. An emergency spillway was cut through a ridge on the west side of the dam, and a stone-covered dike was constructed on the north side of the dam.