Police employees of the State Police are ex officio constables and have the primary role of patrolling the state highways, enforcing the laws and regulations of the highway and motor vehicles, providing law enforcement for municipalities with no or part time coverage, and regulations relating to the transportation of hazardous materials.

New Hampshire RSA 106-B:15[5] sets out that troopers have primary jurisdiction on all turnpikes, toll roads, limited access highways, interstate highways and towns without full time police coverage.

In 2008 the eighty officers of the New Hampshire Highway Patrol of the Division of Motor Vehicles were merged into State Police.

[6] This latest merger has swelled the NH State Police to approximately 380 troopers.

[8] Since the establishment of the New Hampshire State Police, ten officers have died in the line of duty.