- Established (1857)
- Free-State stronghold and Underground Railroad station
- Attacked by U.S. Deputy Marshal John Little (December 16, 1857)
- Abandoned (December 17, 1857)
- Possibly used as a headquarters by John Brown (December 1858)
Fort Bain, a fortified log house capable of housing 50 people, served as a base of operations for radical abolitionists John Brown, James Montgomery, and its namesake, Captain Oliver P. Bain. With its location close to the Missouri border, Brown and Montgomery could stage raids into that state to liberate slaves and usher them to freedom on the "Underground Railroad." The building served as a defensive position against proslavery forces during the "Bleeding Kansas" troubles, and Brown once claimed to have used it to defend against a force of 500 attackers. As a non-military fort, Fort Bain became a target of U.S. Deputy Marshal John Little, based at Fort Scott. Little unsuccessfully attacked Fort Bain on December 16, 1857 and returned the following day to find the fort abandoned. According to legend, John Brown again used the building to plan his famed slave liberation raid into Missouri in December 1858. The structure remained for some years until it was replaced after the Civil War, and today nothing remains at the site.