N.H. Rev. Stat. § 211:5
If the laws of the state of Vermont permit fishing in that part of the Connecticut River lying within that state by persons legally licensed to fish in New Hampshire or otherwise entitled under the laws of this state to fish in that part of said river lying within this state, residents of Vermont legally licensed to fish in the state of Vermont or otherwise entitled under the laws of that state to fish in said part of the Connecticut River lying within the state of Vermont shall be permitted to fish in that part of the Connecticut River lying within this state. If the above reciprocal laws are in effect as to that part of the Connecticut River lying within the states of New Hampshire and Vermont the executive director is authorized to adopt special rules as to fishing in such waters, after consultation with the like officer of the state of Vermont, in the same manner and with the same effect as the executive director is authorized to do with respect to boundary lakes under the provisions of RSA 211:4.
RSA 211:5
1951, 116:1, par. 32-b. RSA 211:5. 1959, 263:1. 1990, 30:1. 1998, 113:1, eff. Jan. 1, 1999.