The Gridley River is a 6.3 miles (10.1 km) 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 southern 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 a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Contoocook River

Contoocook River

The Contoocook River is a river in New Hampshire. It flows from Pool Pond and Contoocook Lake on the Jaffrey/Rindge border to Penacook , where it empties into the Merrimack River. It is one of only a few rivers in New Hampshire that flow in a predominantly northward direction...

, part of the Merrimack River

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...

 watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

. Most of the river's length is within the town of Sharon

Sharon, New Hampshire

Sharon is a town in Hillsborough County, New Hampshire, United States. The population was 352 at the 2010 census.-History:Settled in 1738, Sharon was originally a part of Peterborough...

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The Gridley River begins in Tophet Swamp in the northwestern corner of New Ipswich, New Hampshire

New Ipswich, New Hampshire

New Ipswich is a town in Hillsborough County, New Hampshire, United States. The population was 5,099 at the 2010 census. New Ipswich, situated on the Massachusetts border, includes the villages of Bank, Davis, Gibson Four Corners, Highbridge, New Ipswich Center, Smithville, and Wilder, though these...

, at the juncture of brooks flowing west from the Wapack Range

Wapack Range

The Wapack Range, sometimes referred to as the Pack Monadnock Range, is a 20-mile range of mountains in south-central New Hampshire and adjacent Massachusetts. The range is considered very scenic and rugged with many bare summits and ledges ranging from 1,800 feet to 2,290 feet. The 22 mile Wapack...

. The river soon enters the town of Sharon and heads north through wetlands and intervening steep patches, reaching the Contoocook River just within the southwestern corner of Peterborough

Peterborough, New Hampshire

Peterborough is a town in Hillsborough County, New Hampshire, United States. The population was 6,284 at the 2010 census. Home to the MacDowell Art Colony, the town is a popular tourist destination....

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