The Thurman Station–Warrensburg state highway was designated as NY 418 as part of the 1930 renumbering of state highways in New York. NY 418's alignment has not been substantially altered since that time; however, parts of the route have been upgraded since 1930. In 1933, the original bridge that carried NY 418 over the Schroon River in Warrensburg was replaced with a new truss bridge in length. The route's original bridge over the Hudson River near Thurman Station was replaced in 1941 with the Thurman Station Bridge, another truss bridge long. The bridges were reconstructed by the New York State Department of Transportation in 2000 and 1995, respectively.