The Penobscot River is a 109mi 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 8610sqmi.It arises from four branches in several lakes in north-central Maine, which flow generally east. After the uniting of the West Branch with the East Branch at Medway, the Penobscot flows south, past the city of Bangor, where it becomes navigable. Also at Bangor is the tributary Kenduskeag Stream. It empties into the Atlantic Ocean in Penobscot Bay. It is home to the Penobscot people that live on Indian Island.The United States government maintains three river flow gages on the Penobscot river. The first is on the East Branch in Grindstone (an unincorporated settlement approximately 10mi south of Stacyville) where the rivershed is 1086sqmi. Flow here has ranged from 400 to 1,300cuft/s. The second is in West Enfield where the rivershed is 6671sqmi. Flow here has ranged from 4,410 to 9,660cuft/s. The third is in Eddington, 0.4mi downstream from the Veazie Dam where the rivershed is 7764sqmi.