William Allen was a Boone County slave, residing in the area in the 1840s. He was a friend of John "Felix" White, who had escaped to Michigan and Canada several years before, and may have lived in the area of Rabbit Hash. Allen acted as an agent for the the Underground Railroad in Boone County in the attempted escape of White's wife, children, and Solomon, a slave and overseer on the Stephens plantation. Though Allen himself was attempting to escape, he was instrumental in the planning of this rescue, long before it happened. He met with noted abolitionist Laura Smith Haviland, who was in contact with White, and Allen warned her of river patrols in the area.
The group included Allen, White, Jane (White's wife) and their five children, along with the enslaved overseer from the Stephens plantation, Solomon. The river level was higher than normal, and the current put them downstream of their planned landing, near Rising Sun, IN. The group scattered, and White an Allen eluded capture for a while, but were ultimately caught.
Though there were Allen families in Boone County, there is little information on who owned William Allen, or his fate after he was captured.