Gilford is the only town in New Hampshire named for a Revolutionary War battle: the Battle of Guilford Court House, fought on March 15, 1781, in North Carolina. In that pivotal clash, Major General Nathanael Greene's Continental Army and militia inflicted devastating casualties on General Charles Cornwallis's British regulars. While Cornwallis technically held the field, he lost over a quarter of his force—a Pyrrhic victory that forced the British to abandon the Carolinas and march north toward Virginia, directly paving the road to their surrender at Yorktown.

Following the war, Lt. Lemuel B. Mason, a New Hampshire officer who fought in the engagement, settled in the Upper Parish of Gilmanton. When the community separated in 1812, Mason was honored as its most distinguished veteran with the right to name the town. He chose "Guilford" to commemorate the battle, but a clerical error by a Concord statehouse clerk permanently dropped the "u," giving the town its current spelling.