New Hampshire Route 10 (NH 10) is a north–south state highway in the U.S. state of New Hampshire. Its southern terminus is at the Massachusetts state line in the town of Winchester. In Massachusetts the highway becomes Massachusetts Route 10. Total length of the highway is 122.25 miles (196.74 km).

NH 10 begins at the Massachusetts state line in Winchester, New Hampshire. The road continues into Keene (where it has a short concurrency with NH 9). From Keene, NH 10 travels north via Newport until Grantham. It then runs along I-89 from Grantham to Lebanon. After exiting I-89 and running briefly on US 4, NH-10 then travels along the east bank of the Connecticut River from Lebanon up to its northern terminus at US 302 in Woodsville. Signage for Route 10 continues, however, all the way to Littleton; this portion of the road is co-signed with U.S. 302 until reaching Interstate 93 in Littleton.

In Hanover, NH Route 10 has what is essentially a short spur to Vermont, NH-10A.

NH 10A is an east–west highway in Hanover. It is known as the shortest state highway in New Hampshire.

The eastern terminus of Route 10A is in the center of Hanover at the junction with NH-10, which is Main Street. The western terminus of NH-10A is on the bridge over the Connecticut River, which is the border with Vermont. The road continues into Vermont and becomes Main Street in the town of Norwich. Total length of NH-10A is approximately 0.6 mile (0.9 km). This road is locally named West Wheelock Road in Hanover.