The Belknap-Sulloway Mill, now the Belknap Mill Museum, is a historic mill at 25 Beacon Street East in Laconia, New Hampshire. The 3-1/2 story brick building was built sometime between 1823 and 1828, and is a rare well-preserved example of an early rural textile mill in New England. Unlike later mills, which used more fire-resistant materials, its interior uses joisted floor construction. The mill was in active use for the production of textiles until 1969, undergoing some modest alterations as well as the modernization of its power plant. It was opened as a museum in 1991.