Ohio State Route 10

As part of the "Inter-County Highway" system, Inter-County Highway (later State Route) 10 ran along present-day US 22 from Cincinnati to Zanesville.[3] As part of a 1923 highway renumbering, the route was removed and was replaced by two routes: SR 3 (part) and SR 40. Also part of this renumbering, SR 10 was established along current-day SR 309 and US 30 corridors. Up until then, this corridor was signed as State Routes 127, 128, 112, 114, 206 (part), 202, and 146.[4][5] In 1926, all of SR 10 in the second alignment was cosigned with US 30.[6][7]

With the introduction of the U.S. Numbered Highway System in Ohio, creating duplicate numbers and redundant concurrencies, a 1927 renumbering plan was implemented. As part of this plan, SR 10 was removed from US 30 (now SR 309 and US 30) and was moved to the eastern section of its first alignment. The "third" alignment traveled from Washington Court House to Zanesville.[7][8] In 1932, without any significant changes, SR 10 was removed in favor of US 22's southwest extension from Cambridge. The route then moved onto an Aberdeen–Toledo alignment for one year.[9][10] After that, in 1933, the route became part of US 68's northern extension into Ohio.[10][11]

In 1934, one year after SR 10 was not present, the route reappeared largely on its current alignment, running from Oberlin to downtown Cleveland.[11][12] In 1983, a section of SR 10 from SR 301 to I-80/I-480 became freeway-standard.[13][14] In 1988, SR 10 was truncated to its current western terminus after US 20 moved onto a freeway that was recently upgraded. The remaining route through Oberlin became part of SR 511.[15][16] In 2021, SR 10 was extended eastward to US 322 (Chester Avenue) in the University Circle neighborhood. At its previous eastern terminus at Ontario Avenue, SR 10 turns east and follows Ontario and Orange Avenues (US 422, SR 8, SR 14, SR 43, SR 87) east, turns southeast along a small part of I-77 (Willow Freeway), then exits at the interchange with I-490 (Troy Lee James Highway) heading east along the Opportunity Corridor and north along 105th Street.[17]