The Androscoggin River is a river in Maine and New Hampshire. It is 178 miles long and joins the Kennebec River at Merrymeeting Bay in Maine before its water empties into the Gulf of Maine on the Atlantic Ocean. Its drainage basin is 3,530 square miles in area. The name "Androscoggin" comes from the Eastern Abenaki term meaning "river of cliff rock shelters" (literally "thus-deep-dwelling-river"); or perhaps from Penobscot meaning "river of rock shelters".

The Androscoggin begins in Errol, New Hampshire, where the Magalloway River joins the outlet of Umbagog Lake. The river flows generally south but with numerous bends past the towns of Errol and Milan and the city of Berlin before turning east at the town of Gorham, New Hampshire, to cut across the northern end of the White Mountains and enter Maine.