History of King's Highway 18B (Ruthven):
King's Highway 18B was a very short connector highway in the Leamington area which linked Highway 18 to Highway 3 in Ruthven. A Preliminary Route Plan was prepared on November 25, 1936, showing a proposed King's Highway to be assumed from Ruthven southerly to Highway 18. This tiny highway was assumed by the Department of Highways on August 25, 1937. The route was initially numbered as Highway 18B. At a length of only 1.5 km, it was one of the shortest King's Highways to ever exist in Ontario. Highway 18B shares this honour with the route's subsequent designation, Highway 107. The route of Highway 18B was gravel-surfaced at the time of assumption, but the route was paved in 1944. Highway 18B was renumbered as Highway 107 in 1953. A different, unrelated Highway 18B existed in Amherstburg.