Mill Brook Bogs (formerly Freetown Swamp) WMA consists of shrub swamp, Atlantic white cedar swamp, former cranberry bogs and a large former cranberry bog reservoir, with small areas of mixed upland forest. Common vegetation on the WMA includes red maple, sweet pepperbush, highbush blueberry, leatherleaf, swamp azalea, sphagnum moss, and Atlantic white cedar, with uplands dominated by white pine, red oak, and common greenbrier. Cotton grass, sundew, and other bog plant species are also present.

The WMAs primary access point is a small gravel parking area at the north end of the property on Howland Road approximately 0.10 mile east of the intersection with Rebecca Road (adjacent to where Mill Brook crosses under Howland Road). It is also accessible through Department of Conservation and Recreation property at the Freetown-Fall River State Forest along the eastern side of Slab Bridge Road, approximately 700 feet north of the entrance to the State Forest Headquarters (old campground) or just south of the entrance to Profile Rock. Numerous unofficial and unmarked foot paths lead from the State Forest into the WMA.

This WMA contains one of the largest remaining shrub swamps in southeastern Massachusetts. The property and abutting former cranberry bogs were likely once part of a much larger Atlantic white cedar swamp. Within the remaining cedar and shrub swamp there are several very large boulders left behind by receding glaciers that can clearly be seen in aerial photos. Visitors might hear Whip-poor-wills—a state listed Special Concern species—from the uplands on the eastern side of the property.