The primary purposes of Hamlin Marsh Wildlife Management Area (WMA) are for wildlife management, wildlife habitat management, and wildlife-dependent recreation. This WMA is 1686 acres in size with approximately 88% as wetland habitat. The WMA is about four miles long and from 1/4 to one mile wide. Mud Creek flows into and out of Hamlin Marsh WMA and drops only about 2.4 feet as it travels through the marsh. Mill Creek flows into the marsh from the south side under Bear Road. The marsh appears to have become wetter since the 1940s. Part of this is due to increasing human development around the wetland causing more frequent and faster water runoff into the marsh and is partly due to dams downstream of the marsh. The WMA's topography is gently rolling land with an average elevation of about 400 feet above sea level. In the past, Hamlin Marsh was referred to as Clay Marsh, Cicero Swamp, Little Cicero Swamp, and Peat Swamp. In 1994 it was renamed the Stanley J. Hamlin Marsh WMA after a local prominent conservationist who was instrumental in the state acquisition of the area.