Kinsman Notch is a mountain pass

Mountain pass

A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route...

 located in the White Mountains

White Mountains (New Hampshire)

The White Mountains are a mountain range covering about a quarter of the state of New Hampshire and a small portion of western Maine in the United States. Part of the Appalachian Mountains, they are considered the most rugged mountains in New England...

 of New Hampshire

New Hampshire

New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is the westernmost of the major notches through the White Mountains (the others being Franconia Notch

Franconia Notch

Franconia Notch is a major mountain pass through the White Mountains of New Hampshire. Dominated by Cannon Mountain, it lies principally within Franconia Notch State Park and is traversed by the Franconia Notch Parkway Franconia Notch (el. 1950 ft. / 590 m.) is a major mountain pass through...

, Crawford Notch

Crawford Notch

Crawford Notch is the steep and narrow gorge of the Saco River in the White Mountains of New Hampshire, located almost entirely within the town of Hart's Location...

, and Pinkham Notch

Pinkham Notch

Pinkham Notch is a mountain pass in the White Mountains of north-central New Hampshire, United States. The notch is a result of extensive erosion by the Laurentide ice sheet during the Wisconsinian ice age. Pinkham Notch was eroded into a glacial U-shaped valley whose walls are formed by the...

). To the southeast, the valley of the notch is drained by the Lost River

Lost River (New Hampshire)

The Lost River is a stream located in the White Mountains of New Hampshire in the United States. It is a tributary of the Pemigewasset River, part of the Merrimack River watershed....

, leading to the Pemigewasset River

Pemigewasset River

The Pemigewasset River , known locally as "The Pemi", is a river in the state of New Hampshire, the United States. It is in length and drains approximately...

 and ultimately the Merrimack

Merrimack River

The Merrimack River is a river in the northeastern United States. It rises at the confluence of the Pemigewasset and Winnipesaukee rivers in Franklin, New Hampshire, flows southward into Massachusetts, and then flows northeast until it empties into the Atlantic Ocean at Newburyport...

, flowing into the Gulf of Maine

Gulf of Maine

The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America.It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. It includes the entire coastlines of the U.S...

. The northwest half of the notch is drained by Beaver Brook and the Wild Ammonoosuc River

Wild Ammonoosuc River

The Wild Ammonoosuc River is a tributary of the Ammonoosuc River, about long, in northwestern New Hampshire in the United States. Via the Ammonoosuc River, it is part of the watershed of the Connecticut River, which flows to Long Island Sound....

, part of the Connecticut River

Connecticut River

The Connecticut River is the largest and longest river in New England, and also an American Heritage River. It flows roughly south, starting from the Fourth Connecticut Lake in New Hampshire. After flowing through the remaining Connecticut Lakes and Lake Francis, it defines the border between the...

 watershed leading to Long Island Sound

Long Island Sound

Long Island Sound is an estuary of the Atlantic Ocean, located in the United States between Connecticut to the north and Long Island, New York to the south. The mouth of the Connecticut River at Old Saybrook, Connecticut, empties into the sound. On its western end the sound is bounded by the Bronx...

.

The notch lies between Mount Moosilauke to the southwest and Kinsman Ridge to the northeast. The Appalachian Trail

Appalachian Trail

The Appalachian National Scenic Trail, generally known as the Appalachian Trail or simply the AT, is a marked hiking trail in the eastern United States extending between Springer Mountain in Georgia and Mount Katahdin in Maine. It is approximately long...

 crosses the height of land in the notch on its route between Moosilauke and Kinsman Ridge. The trail descends Moosilauke along Beaver Brook Cascades, a long set of waterfalls descending a total of 1000 feet (304.8 m).

The Lost River Reservation

Lost River Reservation

The Lost River Reservation is a series of caves in the White Mountains in Woodstock, New Hampshire, United States. Located west of the village of North Woodstock on New Hampshire Route 112, Lost River Reservation is set in Kinsman Notch...

, a wild gorge filled with enormous boulders, is found in the floor of the notch to the southeast of the height of land.

New Hampshire Route 112

New Hampshire Route 112

New Hampshire Route 112 is a long east–west state highway in northern New Hampshire. The highway winds across the state, connecting Bath to Conway via the scenic and mountainous area of the White Mountain National Forest. Part of this highway, which runs through the White Mountains, is known as...

 traverses the notch on its route from North Woodstock

North Woodstock, New Hampshire

North Woodstock is a census-designated place in the town of Woodstock in Grafton County, New Hampshire. It had a population of 528 at the 2010 census....

 to Woodsville, New Hampshire

Woodsville, New Hampshire

Woodsville is a census-designated place in the town of Haverhill in Grafton County, New Hampshire, U.S., along the Connecticut River at the mouth of the Ammonoosuc River. The population was 1,126 at the 2010 census...

.