Gilmanton Ironworks is an unincorporated community in the town of Gilmanton in Belknap County, New Hampshire, United States. It is located near the eastern boundary of the town, along a stretch of the Suncook River south of the outlet of Crystal Lake. New Hampshire Route 140 runs through the village, leading east to Alton and west to the center of Gilmanton and then Belmont. The Gilmanton Ironworks ZIP code serves the eastern portion of the town of Gilmanton.