 Between 1918 and 1926, Route 46 was extended to Sheridan. Soon after, in 1933, it extended south, two miles east of Sheridan. The extension caused the road to Sheridan to become a spur route of Route 46. The spur route was then extended west into Nodaway County around 1948 – 1949, and was numbered supplemental route D. Four years later, the route was extended to Route 27 (now Route 148). In 1954, Route 246 was designated, starting from Sheridan, and ending at Route 46. The next year, Route 246 was extended to replace supplemental route D as the main connector from Hopkins to Route 46. The whole route was surfaced in concrete by 1959.
