Beaver Dam State Park is a state park and recreational facility in Plainview, Illinois. It is part of the Illinois State Park System and, as such, is operated by the Illinois Department of Natural Resources.

The Beaver Dam State Park is centered on the Beaver Dam Lake. The lake itself was well known fishing spot during the 1890?s. 18 local citizens from the Carlinville area formed the Beaver Dam Lake Club which built dams at both ends of the lake which doubled the water depth in the lake. The area then came into use as a fishing and boating area for the people of the area. The state acquired the current park through land acquisition in 1947. The state increased the park size to about 751 acres by further land acquisitions around the original park.