Cockaponset State Forest is the second largest forest in the Connecticut state forest system, encompassing over 16,000 acres (65 km²) of land. Most of the land is in Middlesex County though some parcels lie in New Haven County. The forest is disjointed, and comprises land in the towns of Haddam, Chester, Deep River, Killingworth, Durham, Guilford, Madison, Clinton, Westbrook, Middletown and Middlefield.