The 1863 New Hampshire gubernatorial election was held on March 10, 1863.
Incumbent Republican Governor Nathaniel S. Berry did not stand for re-election.
Republican nominee Joseph A. Gilmore defeated Democratic nominee Ira Allen Eastman and Union Democrat Walter Harriman.
Since no candidate received a majority in the popular vote, Gilmore was elected by the New Hampshire General Court per the state constitution.
As no candidate received a majority of the vote, the New Hampshire General Court was required to decide the election, both Houses in convention choosing among the top two vote-getters, Eastman and Gilmore. The legislative election was held on June 4, 1863.