The Bristol-Plymouth county line runs through Hockomock Swamp Wildlife Management Area. Birders who carefully keep bird records by county should be aware of the location of the county line.

The original Hockomock was a vast wet and wooded area of 6,000 or more acres, perhaps as much as 10,000 acres, but, over three centuries of immigrant occupation, it has been bisected by roads, power lines, and a railroad line, and the perimeter has been nibbled away by filling for developments. At present, the state holds title to 4,454 acres as the Hockomock Wildlife Management Area, 450 acres as the adjacent Wilder Wildlife Management Area, and 222 acres as the nearby West Meadows Wildlife Management Area. As opportunities arise, more land is added. Hockomock consists of large areas of Atlantic Coastal White Cedar, other areas of Red Maple swamp, small open ponds in addition to Lake Nippinicket, and some open marsh. The area surrounding Nippinicket Pond has been designated an Area of Critical Environmental Concern, and much of the pond itself is bounded by the Hockomock Swamp Wildlife Management Area. Eugene S. Wilder Wildlife Management Area is an abandoned farm still maintained as open fields with some mixed stands of hardwoods, pine, and hemlock. West Meadows Wildlife Management Area is a large reservoir maintained by a dike and surrounded by wet woodland, and a mix of pines and hardwoods.

As fragmented as it is, the greater Hockomock area is still huge, providing habitat for birds, mammals, herps, and invertebrates, as well as a diverse flora. The very swampy terrain means it is still relatively unknown except where accessed by a power line or abandoned railroad dike. The area has contained nine breeding and/or wintering/migrant state-listed species, and at least 47 regional and five state high conservation priority species. Very abundant species are Gray Catbird, Northern Waterthrush, Common Yellowthroat, Swamp Sparrow, and Common Grackle. Veeries were also plentiful although not as abundant as the previously listed species.