The governor's signature marks the conclusion of a months-long campaign to end child marriage in the state after the nonprofit organization, Unchained at Last, and two Democratic lawmakers brought attention to the issue in February.
The latest version of the law passed through the legislature in April and is now in effect.
The nonprofit pointed out that previous law allowed a judge to waive the minimum age limit for marriage if guardians of a child consented. The group found the loophole had allowed numerous cases of children 16 and younger to marry and cited higher divorce rates and instances of abuse for married minors.