South Branch Penobscot River

South Branch Penobscot River
Location
CountryUnited States
Physical characteristics
Source 
  locationMaine
  elevation1,860 feet (570 m)
Mouth 
  location
Seboomook Lake
  coordinates
45°53′53″N 69°57′58″W / 45.898°N 69.966°W / 45.898; -69.966
  elevation
1,070 feet (330 m)
Length39 miles (63 km)
Basin features
ProgressionWest BranchPenobscot River

The South Branch Penobscot River is a river in Somerset County, Maine. Its source, Penobscot lake, the north end of which at (45°47′34″N 70°24′36″W / 45.7929°N 70.4099°W / 45.7929; -70.4099 (South Branch Penobscot River source)) is about 1,000 feet (300 m) from the Canada–United States border in Sandy Bay (Maine Township 5, Range 3, NBKP). This section of the border runs along the height of land separating the watersheds of the Penobscot River and the Monument River, which feeds into the Saint Lawrence River.

The South Branch of the Penobscot River runs 39.0 miles (62.8 km) northeast through Canada Falls Lake to its drowned confluence with the North Branch of the Penobscot in Seboomook Lake in Pittston Academy Grant (T.2 R.4 NBKP). The two rivers combine to form the West Branch Penobscot River, which flows east from the outlet of Seboomook Lake.