The Interstate 93 highway runs parallel with the river between Franconia Notch and New Hampton. The river passes through the communities of Lincoln, North Woodstock, Woodstock, Thornton, Campton, Plymouth, Ashland, Bridgewater, Bristol, New Hampton, Hill, Sanbornton, and Franklin.
The river descends over waterfalls in Franconia Notch, including The Basin, passes cascades in North Woodstock, and drops over Livermore Falls north of Plymouth. The remainder of the northern Pemi, from Lincoln to Ashland, is a braided river that passes over copious gravel bars and attracts numerous boaters and fishermen. Below Ashland, the river is impounded by the Ayers Island Dam, a hydroelectric facility, for over five miles. A short stretch of heavy whitewater is found below the dam, before the river reaches the impoundment zone for the Franklin Falls flood control reservoir. The river crosses one additional hydroelectric dam below Franklin Falls before joining the Winnipesaukee River in the center of Franklin.
The Pemigewasset watershed consists of over 1100 miles of rivers and of lake, pond, and reservoir area. The watershed comprises about 20 percent of the Merrimack's total watershed area.
Major tributaries include (from north to south):