History of King's Highway 7C:
King's Highway 7C was a short highway which linked Highway 28 to Highway 7 in the Peterborough area during the 1930s. This route was originally thought to have been a portion of Highway 7A, but a historical reference was recently discovered which indicates that the highway was initially numbered as Highway 7C when it was first established in 1933. The proposed route of Highway 7C was first shown on a Preliminary Route Plan dated October 4, 1933. The route began at the intersection of Highway 28 (today's Clonsilla Avenue) west of Peterborough and followed Lansdowne Street into the city. The route of Highway 7C ended at Haggart Street (Highway 7) immediately west of the Otonabee River Bridge. The 2.6-mile route of Highway 7C was assumed by the Department of Highways of Ontario (DHO) on November 29, 1933. The new route allowed through traffic headed between Highway 7 and Highway 28 to bypass Downtown Peterborough. The entire route of Highway 7C was paved in 1936.
The route of Highway 7C was rather short-lived. In 1938, a new King's Highway was designated between Highway 7 & Highway 12 and Highway 28, via Port Perry and Bethany. This new route was designated as Highway 7A. It was decided that the route of Highway 7A would be continued through to Peterborough to improve route continuity. The route of Highway 7A was overlapped with Highway 28 south of Peterborough, and the route of Highway 7C via Lansdowne Street was renumbered as Highway 7A. The route number change apparently took place early in 1938, as road condition bulletins issued by the DHO in mid-1938 identify the new highway between Port Perry and Peterborough as Highway 7A.
The meaning of the peculiar "C" suffix assigned to this route is uncertain, and is especially perplexing given that the Highway 7C designation was assigned 5 years prior to the establishment of Highway 7A and more than two decades prior to the creation of the Highway 7B designation. The only other highways that were assigned a "C" suffix in Ontario were Highway 3C near Fort Erie and Highway 40C in Sarnia.