The Little River is a 4.6 mile

Mile

A mile is a unit of length, most commonly 5,280 feet . The mile of 5,280 feet is sometimes called the statute mile or land mile to distinguish it from the nautical mile...

 long (7.4 km

KM

KM, Km, or km may stand for:*Kilometre *Kernel methods*Kettle Moraine High School*Khmer language *Kuomintang , a centre-right political party in the Republic of China on Taiwan...

) river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 located in southeastern 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...

 in the United States

United States

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

. It is located entirely in the town of North Hampton

North Hampton, New Hampshire

North Hampton is a town in Rockingham County, New Hampshire, United States. The population was 4,301 at the 2010 census. While the majority of the town is inland, North Hampton includes a part of New Hampshire's limited Atlantic seacoast.-History:...

, and it flows directly into the Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, south of Little Boars Head.

The river rises in a forested wetland

Wetland

A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

 in the northern part of North Hampton and flows south, passing under U.S. 1

U.S. Route 1 in New Hampshire

In the U.S. state of New Hampshire, U.S. Route 1 is a major north–south state highway through Hampton and Portsmouth. It lies between Interstate 95 and New Hampshire Route 1A.-History:...

. The river

Tidal river

A tidal river is a river, or more typically a stretch of a river, whose flow and level is influenced by tides. An example of a tidal river is the portion of the Connecticut River flowing from Windsor Locks, Connecticut, to the Atlantic Ocean. The Brisbane River, which flows into the Pacific Ocean...

 turns southeast, passes through Mill Pond and under NH 111

New Hampshire Route 111

New Hampshire Route 111 is a east–west highway in Hillsborough and Rockingham counties in southeastern New Hampshire. The road runs from Hollis to North Hampton on the Atlantic shore....

, and enters the Little River salt marsh

Salt marsh

A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...

. The river enters the Atlantic Ocean by passing under NH 1A

New Hampshire Route 1A

New Hampshire Route 1A is an long state highway located in southeast New Hampshire. The route runs along the Atlantic coastline from the Massachusetts border north to Rye, then turns toward downtown Portsmouth. The southern terminus is at the Massachusetts state line in Seabrook at the junction...

, using a new, large culvert installed by the New Hampshire Coastal Program in an effort to improve tidal flow into the salt marsh.