The Contoocook River is a major waterway in southern New Hampshire, flowing approximately 71 miles from its headwaters near Jaffrey to its confluence with the Merrimack River in Penacook. It is one of the few rivers in the state that flows in a generally west-to-east direction. The river offers diverse paddling opportunities, from calm flatwater sections to challenging whitewater. The upper reaches near Jaffrey and Peterborough provide scenic flatwater and Class I-II rapids suitable for novice paddlers. The middle section between Hillsborough and Henniker features the famous Class IV Freight Train rapids, a favorite among experienced whitewater enthusiasts. The lower sections near Concord offer peaceful flatwater paddling through forested landscapes.

Paddling difficulty ranges from easy flatwater to Class IV whitewater, requiring varying levels of skill. The river is generally best paddled from late spring through early fall, with higher water levels in spring providing the best whitewater conditions. Fall foliage season offers spectacular scenery for flatwater paddlers.

The Contoocook's ecosystem supports diverse wildlife, including great blue herons, bald eagles, and various fish species. Paddlers often encounter turtles basking on logs and may spot deer along the shoreline.

Key landmarks include the Contoocook Railroad Bridge, one of the oldest covered railroad bridges in the U.S., and several historic mill towns along the river's course. Powder Mill Pond, a scenic impoundment near Bennington, is a popular flatwater paddling destination.

Major access points include Riverway Park in Contoocook Village, the put-in for a popular 9-mile trip, and various locations in Jaffrey, Peterborough, Hillsborough, and Henniker. The Contoocook River Canoe Company in Concord offers rentals and shuttles for day trips.

Historically, the river powered numerous mills and was crucial to the region's industrial development. Today, it's valued for recreation and its natural beauty.

Safety considerations include checking water levels before paddling, especially for whitewater sections, and being aware of dams and portage points. Life jackets are required by state law. Multi-day trips are possible, particularly on the lower sections, though most paddlers opt for day trips due to the river's accessibility and the availability of put-in and take-out points along its course.