From the dam at the outlet of Lake Winnipesaukee in the Lakeport section of Laconia, the river almost immediately enters Opechee Bay.

1 mile (1.6 km) down the lake, the river exits over a dam and drops through the center of Laconia, its banks lined by industrial buildings from the 19th century that were constructed to take advantage of the river's power.

The river's lower section begins at the natural outlet of Silver Lake, on the boundary between Belmont and Tilton, New Hampshire.

The river passes through the center of the twin towns of Tilton and Northfield, then descends through a narrow valley to Franklin where additional small dams use the river's power.

From Tilton to Franklin, the river has a drop of up to 90 feet per mile (17 m/km), with challenging rapids for sport boaters who put in at Cross Mill Bridge and take out at the U.S. Route 3 Sanborn Bridge in downtown Franklin.