Newfound Lake is located in Grafton County, New Hampshire, USA, within the towns of Bridgewater, Bristol, Alexandria, and Hebron. The lake is located in a section of New Hampshire known as the Lakes Region. At 4,451 acres, it is the third-largest lake located entirely in New Hampshire. The lake's water is refreshed twice-over annually by underground springs. The lake is about 2½ miles wide and 6 miles (9.7 km) long and has a maximum depth of 183 feet (56 m). Major tributaries include the Fowler River and the Cockermouth River. Its outlet is the Newfound River, flowing into the Pemigewasset River.

Wellington State Park, containing a large public beach, is located on the lake's west shore in the town of Bristol.

The Lakes Region of New Hampshire is the mid-state region surrounding Lake Winnipesaukee, Winnisquam Lake, Squam Lake, and Newfound Lake. The area is a popular tourist destination in the summer time, with the activity peaking during the annual Motorcycle Week and races at Loudon's New Hampshire Motor Speedway.

The Newfound River is a 3.2-mile-long (5.1 km river located in central New Hampshire in the United States. It is a tributary of the Pemigewasset River, part of the Merrimack River watershed. The Newfound River begins at the outlet of Newfound Lake in Bristol, New Hampshire. The river drops rapidly through the town of Bristol, passing over several hydroelectric dams before reaching the Pemigewasset. Major tributaries of the Newfound River (via Newfound Lake) are the Fowler River and the Cockermouth River.