Coos, New Hampshire refers to the frontier area of northern New Hampshire. During the American Revolution a military command was located at Haverhill, New Hampshire to protect the New Hampshire Grants and to support military efforts in the invasion of Canada. The name was later given to a portion of northern Grafton County in 1803 when a new county, named Coos, was created. The location was originally a name associated with a part of the migratory Abenaki tribe. The location was known before 1704 to have military significance for several provincial governments and the leaders in New France.