Ackley Lake State Park in central Montana lies about four miles southwest of Hobson and includes a 290-acre recreation area centered on 160-acre Ackley Lake, with views of the Little Belt and Snowy Mountains. The lake began as a 40-acre natural pond owned by Jean Acley and was enlarged in 1938 into an off-stream reservoir by construction of an earthen embankment dam supplied by a canal from the Judith River. The surrounding site became Ackley State Park in 1940. Today it supports fishing, boating, picnicking, and camping, with stocked trout, two boat ramps, and a 26-site campground.