Bonham State Park 
1363 State Park 24
Bonham, TX 75418
903-583-5022
http://tpwd.texas.gov/state-parks/bonham
State Park: Bike, Birding, Camp, Fish, Hike, Picnic, RV, Walk, Water Sports
There is (unsupervised) swimming and fishing in the man-made lake, built in 1935, as well as camping, picnicking, mountain biking, boating (5 mph speed limit).