The 30 acre Hirst Marsh was a naturally occurring wetland created by beaver activity. When beaver became inactive, the NH Fish and Game Department constructed a concrete dam to maintain the water level and the exceptional waterfowl habitat this marsh provides. The marshland vegetation is comprised mainly of cattails, grasses and sedges along the edge with emergent aquatic vegetation species of bur reed, pickerelweed, watershield, and white water lilies surrounding open marsh. A small island with shrubby vegetation provides excellent nesting cover for ground-nesting waterfowl.