N.H. Rev. Stat. § 457:3
Every marriage legally contracted outside the state of New Hampshire, which would not be prohibited under RSA 457:2 if contracted in New Hampshire, shall be recognized as valid in this state for all purposes if or once the contracting parties are or become permanent residents of this state subsequent to such marriage, and the issue of any such marriage shall be legitimate. Marriages legally contracted outside the state of New Hampshire which would be prohibited under RSA 457:2 if contracted in New Hampshire shall not be legally recognized in this state. Any marriage of New Hampshire residents recognized as valid in the state prior to the effective date of this section shall continue to be recognized as valid on or after the effective date of this section. Notwithstanding anything in this statute or the provisions of RSA 457:43 to the contrary, any marriage of a same-sex couple lawfully contracted outside New Hampshire shall be recognized in New Hampshire as of the date of its solemnization.
RSA 457:3
RS 147:3. CS 156:3. GS 161:3. GL 180:3. PS 174:3. PL 286 :3. RL 338:3. RSA 457:3. 1965, 252:1. 1973, 145:6. 2004, 100:1. 2009, 59:1. 2014, 160:1, eff. July 10, 2014.