The Squam River first appears as a narrow channel in Holderness, New Hampshire, between Squam Lake and Little Squam Lake downstream. The two lakes have the same elevation, due to a dam below the outlet to Little Squam, so the river in Holderness village is not free-flowing. Below Little Squam Lake the river proceeds south for over a mile before reaching the dam which controls the two lakes' water level. Below this point, the river quickly reaches the backwater from a mill dam in the town of Ashland.
In Ashland, the river drops 50 feet (15 m) in 0.2 miles (0.3 km), sufficient to provide hydropower for numerous industries when the town originally grew in the 19th century. Below the center of town, the river wanders southeast under railroad tracks and Interstate 93 and past the Ashland sewage treatment plant before entering the Pemigewasset River in the northwest corner of the town of New Hampton.
