Hampden is a town on the Penobscot River estuary in Penobscot County, Maine, United States. The population was 7,709 at the 2020 census. Hampden is part of the Bangor metropolitan statistical area.

The Penobscot River is a 109-mile-long (175 km) river in the U.S. state of Maine. Including the river's West Branch and South Branch increases the Penobscot's length to 264 miles (425 km), making it the second-longest river system in Maine and the longest entirely in the state. Its drainage basin contains 8,610 square miles (22,300 km2).