Tunnel No. 1 is located on the former Cincinnati, Hamilton & Dayton Railroad (CH&D) Ironton Branch near Hoadley, Ohio. The tunnel, completed in 1882 by the Toledo, Cincinnati & St. Louis Railroad (TC&StL),3 featured a brick lining.
In 1916, under the CH&D, work commenced on improvements to the tunnels along the Ironton Branch but flooding later in the year washed out substantial portions of the CH&D south of Wellston. The railroad opted to abandon the route from Wellston to Dean Junction, including tunnels no. 1, no. 2, and no. 3.1 2