The Township of Sloan was founded on June 8, 1875. The town was named after Samuel Sloan, who worked with John I. Blair and the Sioux City and Pacific Railroad. When a station was added in the area, it was named after Samuel Sloan. The section of land on which Sloan is located was donated to Mr. Blair by Rufus Beall who owned hundreds of acres of land surrounding the town site.
The choice to incorporate the town of sloan where it is located was unusual as it lacked several features common to all other townships of Woodbury County. It had no lake, spring or stream, nor any trees. All trees were planted in later years.
The first church was erected in 1881. The town was officially incorporated in 1883.