Eaglehead Woods lies south of the MBTA railroad tracks that mark the southerly boundary of Sweeney Playground on Summer Street. It is an extensive swamp behind the cluster of homes atop Eaglehead. A smaller swamp lies slightly to the west, backing onto the railroad tracks behind Spy Rock Hill and extending toward Old Neck Road. The Eaglehead swamps are wooded and include several shallow ponds. These swamps are important for flood prevention in the Summer Street-Lincoln Street and Beach Street areas in that they decelerate the release of runoff from the areas they drain.

The topography of this area is relatively flat, with a gradient of about 10 feet overall. These swamps take runoff from steep surrounding hills. The easterly swamp is fed by a seasonal stream exiting Dexter Pond, at the foot of Long Hill and the westerly one by local runoff. The easterly swamp drains via Causeway Brook, which empties into Sawmill Brook near Lincoln Street. The second Eaglehead swamp contains the headwaters for Day's Creek, which empties into the harbor. As Eaglehead homes are at a considerably higher elevation than the swamp, flooding poses no problems to residences, though high groundwater often floods the nearby Sweeney Park playing fields.

There are trails accessible from Eaglehead Road and Sweeney Park.