Question: The Sheepscot River connects to a river that is entirely in the state of maine, and is how long?

Context paragraphs:
West Branch Sheepscot River: The West Branch Sheepscot River is a 24.9 mi river in Maine.  The branch originates in the northwest corner of Palermo ( ) and flows southwesterly through Branch Pond and the village of Weeks Mills in the town of China.  The branch then flows southerly through the town of Windsor to a confluence with the Sheepscot River between Coopers Mills and North Whitefield.  The branch is bridged by Maine State Route 3 between Branch Pond and Weeks Mills, by Maine State Route 105 at Windsor and by concurrent Maine State Routes 17 and 32 near Coopers Mills.

Sasanoa River: The Sasanoa River is an 8.6 mi tidal channel in the Midcoast region of Maine, connecting the Kennebec River with the Sheepscot River.

Sheepscot River: The Sheepscot River is a 66 mi river in the U.S. state of Maine.  Its lower portion is a complex island estuary with connections to the Kennebec River downstream of Merrymeeting Bay.

Dyer River: The Dyer River is a 20.2 mi river in Maine.  It originates along the northern boundary of the town of Jefferson with the town of Somerville ( ) and flows southwesterly through Jefferson, passing through Dyer Long Pond and near South Jefferson.  It continues southwest into the town of Newcastle, passing the villages of North Newcastle and Sheepscot, where it joins the tidal Sheepscot River.

Kennebec River: The Kennebec River is a 170 mi river entirely within the U.S. state of Maine.

Back River (Sheepscot River): The Back River is a 4.8 mi tidal channel in the town of Boothbay, Maine, in the United States.  It defines the east and south sides of Barters Island and connects with the Sheepscot River, which forms the west side of the island.  The Cross River joins the north end of the Back River with the Sheepscot River to the west.

Maine State Route 218: State Route 218 (SR 218) is a 21 mi state highway in Lincoln County, Maine.  The road connects U.S. Route 1 (US 1) and SR 27 at Wiscasset and SR 17/SR 32 in the town of Whitefield.  Throughout its whole route, SR 218 parallels the Sheepscot River.

Sheepscot Historic District: The Sheepscot Historic District encompasses a historic village in Alna and Newcastle, Maine.  Located just below the mouth of Dyer Brook where it enters the Sheepscot River, the 1200 acre includes an area that has seen little alteration in more than 100 years, and includes one of the oldest roadways in the state.  The area is archaeologically sensitive for prehistoric and historic settlement sites.  The district was added to the National Register of Historic Places on June 23, 1978.

Little River (Georgetown, Maine): The Little River is a 4.0 mi river in the town of Georgetown, Maine.  It flows directly into the Atlantic Ocean, between the mouth of the Sheepscot River to the east and the Kennebec River to the west.  The lower portion of its course forms the western boundary of Reid State Park.

Marsh River (Maine): The Marsh River is a 3.9 mi tidal river in Newcastle, Maine, in the United States.  It is a tributary of the Sheepscot River.

Supporting paragraphs: Sheepscot River Kennebec River
Answer: 170 mi