The state park centers on the 59-acre (24 ha) Beaver Dam Lake, an artificial reservoir which was created by a private Carlinville fishing club in the 1890s.

The IDNR manages Beaver Dam Lake for the fishing of largemouth bass, bluegill, channel catfish, and sunfish.

In addition, the park offers opportunities for the hunting of deer, wild turkey, and small game.

There is a power limit for boats using the Beaver Dam Lake reservoir, with no gasoline-powered motors allowed.

Beaver Dam State Park preserves part of the historic oak-hickory forests that line upper Macoupin Creek.