The East Branch Penobscot River is a 75.3 miles (121.2 km) tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of Maine

Maine

Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

's Penobscot River

Penobscot River

The Penobscot River is a river in the U.S. state of Maine. Including the river's West Branch and South Branch increases the Penobscot's length to , making it the second longest river system in Maine and the longest entirely in the state. Its drainage basin contains .It arises from four branches...

. From its source (46.2670°N 69.2023 °W) in Maine Township 7, Range 11, WELS, in Piscataquis County

Piscataquis County, Maine

Piscataquis County is a county located in the U.S. state of Maine. In 2010, its population was 17,535, making it Maine's least-populous county. Its county seat is Dover-Foxcroft....

, the river runs 17 miles (27.4 km) southeast to Grand Lake Matagamon in the northeast corner of Baxter State Park

Baxter State Park

Baxter State Park is a large wilderness area permanently preserved as a state park, located in Piscataquis County in north-central Maine. The Park was established by 28 donations of land, in Trust, from Park donor Percival P. Baxter between the years of 1931 and 1962, eventually creating a Park of...

. From Grand Lake Dam, the river runs 48 miles (77.2 km) south to its confluence

Confluence

Confluence, in geography, describes the meeting of two or more bodies of water.Confluence may also refer to:* Confluence , a property of term rewriting systems...

 with the Penobscot's West Branch

West Branch Penobscot River

The West Branch Penobscot River is a tributary of Maine's Penobscot River. The river flows from Seboomook Lake in Seboomook, Somerset County; the lake's principal inflows are the North Branch and South Branch Penobscot River...

 in Medway

Medway, Maine

Medway is a town in Penobscot County, Maine, United States. The population was 1,489 at the 2000 census.-Geography:According to the United States Census Bureau, the town has a total area of , of which, of it is land and of it is water...

, Penobscot County

Penobscot County, Maine

Penobscot County is a county located in the U.S. state of Maine. For U.S. Census statistical purposes, it is part of the Bangor, Maine, New England County Metropolitan Area . As of 2010, the population was 153,923...

.