Slope Creek Reservoir, also known as Barnesville Reservoir #3, is located in Belmont County in the eastern part of the state. The entire lake lies within Somerset Township. Slope Creek Reservoir is located five miles south of Barnesville off McGinnis Road.

Slope Creek Reservoir was created by the city of Barnesville for water supply and recreational purposes. The lake was formed by damming Slope Creek, which created this 89-acre impoundment. The area around Slope Creek Reservoir consists of sandstone hills and valleys which are covered by second-growth forest. This area was one of the earliest areas settled in Ohio and has a rich local history.