Most of the population occupies roughly one-quarter of the city's land. Pittsfield lies at the confluence of the east and west branches of the Housatonic River, which flows south from the city towards its mouth at Long Island Sound, some distant. The eastern branch leads down from the hills, while the western branch is fed from Onota Lake and Pontoosuc Lake (which lies partly in Lanesborough). Like much of western Berkshire County, the city lies between the Berkshire Hills to the east and the Taconic Range to the west. Sections of the Housatonic Valley Wildlife Management Area dot the banks of the river. The western portion of the city contains Pittsfield State Forest, an facility with hiking and cross-country skiing trails, camping, picnic areas, and a beach for swimming.