RSA 457:45: Civil Union Recognition.

A civil union legally contracted outside of New Hampshire, or any legal union other than a marriage that provides substantially the same rights, benefits and responsibilities as a marriage that is legally contracted outside of New Hampshire, shall be recognized as a marriage in this state, and any person in such legal union contracted outside of New Hampshire may also marry the same party in New Hampshire without the dissolution of such legal union, provided that the relationship does not violate the prohibitions of this chapter.