N.H. Rev. Stat. § 12-A:1-d

I. The commissioner of the department of natural and cultural resources, the director of the division of parks and recreation, and the director of the division of forests and lands shall have authority as peace officers as provided in RSA 594 and may confer said authority upon certain individuals within the department of natural and cultural resources, the division of parks and recreation, and the division of forests and lands. Said police powers shall be limited to the enforcement of state laws and rules of the department of natural and cultural resources on lands or property owned by, leased to, or otherwise under the control of the department of natural and cultural resources. Nothing herein shall limit the police powers of employees of the department of natural and cultural resources as provided for in RSA 227-G:7, RSA 215-C:32, and RSA 215-A:16 and 17. II. By written agreement executed by the commissioner of the department of natural and cultural resources, any authorized municipal official may utilize the summons procedures under RSA 31:39-d to cite individuals for violations of state park administrative rules or forests and lands administrative rules, or both. Authorized municipalities acting under this paragraph shall retain 100 percent of any fine collected in accordance with the schedule of administrative fines of the department of natural and cultural resources.