The New Hampshire Minimum Wage is merely a reference to the US Federal Minimum Wage. This means that if the federal minimum wage is increased or decreased, the New Hampshire one merely matches that.
From RSA 279:21:
Unless otherwise provided by statute, no person, firm, or corporation shall employ any employee at an hourly rate lower than that set forth in the federal minimum wage law, as amended.
The law outlines many exceptions, for instance:
I. These limitations shall not apply to employees engaged in household labor, domestic labor, farm labor, nor to outside salesmen, nor to employees of summer camps for minors.
II. These limitations shall not apply to employees engaged as newsboys, non-professional ski patrolmen or golf caddies.