N.H. Rev. Stat. § 14:15-a

A member of the general court shall be allowed mileage by choosing the method in either paragraph I or II prior to the first mileage reimbursement payment in the term: I. (a) In the computation of mileage under the provisions of this paragraph, the word "day" shall be deemed to be a calendar day; and, whenever a legislative session shall be continued beyond 12 o'clock midnight, the members present shall be entitled to additional mileage for another day's attendance; provided, however, that any member of the general court absent for any cause from such attendance shall not be allowed mileage for the day the member is so absent. (b) A member of the general court shall be allowed mileage for the round trip to and from the member's home to the state house in Concord or, as of January 1, 2022, any location where the member's body convenes for each day of attendance at the following rates: (1) For the first 45 miles, $.38 per mile; and (2) For all miles in excess of 45 miles, $.19 per mile. II. A member of the general court shall be allowed compensation for actual travel expenses of the round trip to and from the member's home to the state house in Concord or, as of January 1, 2022, any location where the member's body convenes. Mileage shall be paid at the maximum rate established in the United States Internal Revenue Code and Regulations for the number of miles traveled.