1924 – Original route established.[2] Originally routed along the current alignments of State Route 571 from the Indiana state line in Union City to 1-mile (1.6 km) east of Greenville, U.S. Route 36 from 1-mile (1.6 km) east of Greenville to Urbana, and its current alignment from Urbana to 2 miles (3.2 km) west of West Jefferson.[3]
1932 – The route was truncated at Urbana; alignment from Union City to Greenville designated as State Route 71; Greenville to Urbana designated as U.S. Route 36.[3]
1939 – The route was extended to the Indiana state line along the former State Route 54 alignment (which was State Route 32 before 1938).[3]
^Explanation of the Ohio State Highway System (The Unofficial Ohio State Highways Web Site) by John Simpson[unreliable source] Archived May 23, 2006, at the Wayback Machine
^ a b c dRoute 29 (The Unofficial Ohio State Highways Web Site) by John Simpson[unreliable source] Archived December 16, 2004, at the Wayback Machine