Ontario Highway 503 History - The King's Highways of Ontario

Secondary Highway 503 was a long collector highway in the Counties of Victoria, Simcoe, Peterborough and Haliburton that extended from Kirkfield located northeast of Beaverton to Tory Hill located west of Bancroft. Originally, Highway 503 was considerably shorter. As first established in 1956, Highway 503 extended from the Highway 48 Junction (formerly known as Highway 46) in Kirkfield northwesterly to the Monck Road at Sebright. At Sebright, the highway turned easterly along the Monck Road via Uphill, Head Lake and Norland and came to an end at the Highway 121 Junction in Kinmount.

The history of Highway 503 dates back to 1956, when a new Secondary Highway route series was designated throughout Northern, Central and Eastern Ontario. The proposed route of Highway 503 from Kirkfield to Kinmount was first depicted on a Preliminary Route Plan prepared by the Department of Highways of Ontario (DHO) dated April 1956. Highway 503 was designated as a Secondary Highway by an Order-in-Council, effective May 9, 1956. The new route of Highway 503 and was approximately 49 miles (79 km) in length when it was first established in 1956. A primed bituminous surface was laid along the entire length of Highway 503 during 1956. The route remained more or less unchanged until 1964, when the highway was extended easterly from Kinmount to Tory Hill. During that year, a major highway route renumbering took place in Central Ontario which saw a portion of Highway 500 between Kinmount and Tory Hill renumbered as an easterly extension of Highway 503. The change in route numbers came into effect on March 1, 1964. In order to unite the eastern and western legs of Highway 503 together at Kinmount, the highway was signed concurrently with Highway 121 for a distance of about 200 metres. The total length of Highway 503 grew to approximately 75 miles (121 km) following the extension of Highway 503 from Kinmount to Tory Hill in 1964. The former route of Highway 500 was already paved in its entirety between Kinmount and Tory Hill at the time that route was renumbered as an easterly extension of Highway 503.

Paving work on Highway 503 began in 1957, when mulch asphalt was placed along the highway from Norland westerly for a distance of 2 miles and also from Sebright easterly for a distance of 6 miles. In 1958, Highway 503 was surfaced from Kirkfield northerly for 2 miles and from Kinmount westerly for 2 miles. An additional 3 miles of mulch asphalt surfacing took place west of Kinmount in 1959. Highway 503 was surfaced with a mulch asphalt from the Highway 505 Junction easterly for 4 miles in 1961, with an additional 3 1/2 miles of mulch asphalt surfacing taking place from 2 miles north of Kirkfield northerly in 1962. About 4 1/2 miles of mulch asphalt was placed along Highway 503 from west of Norland westerly to about 1/2 mile west of Head Lake in 1964. An additional 2 miles of mulch asphalt was placed along Highway 503 from west of Head Lake westerly for about 2 miles in 1965. Within Digby and Laxton Townships, paving was completed in 1966. This project completed a hard surface along Highway 503 between the Highway 35 Junction at Norland and Sebright. Bituminous surface treatment was applied to the final gravel sections situated between Norland and Kinmount in 1967, which completed a hard surface link along Highway 503 between Sebright and Tory Hill. About 5 miles of paving was completed north of the Dalrymple Narrows Bridge in 1976. Highway 503 was first shown with a completely paved surface on the 1977 Edition of the Ontario Official Road Map.

Apart from some minor realignments over the years, no major changes were made to the route of Highway 503 until the 1990s, when jurisdiction over the entire highway was transferred from the province to the municipal tier. On January 1, 1998, provincial jurisdiction over Highway 503 was transferred over to the Counties of Victoria, Simcoe, Peterborough and Haliburton. It became the longest Secondary Highway to be transferred in its entirety to the municipal tier during the highway mass downloading spree of 1997-1998. Although sections of the highway are still commonly referred to by motorists as "Highway 503", this former provincial highway is now officially known as Kawartha Lakes Road 6 from Kirkfield northwesterly to the Simcoe County Boundary. Along the Simcoe County Boundary, Highway 503 is now signed as Kawartha Lakes Road 6 & Simcoe Road 46. At Sebright, the former route of Highway 503 turns east. From Sebright easterly to Kinmount, Highway 503 is now officially known as Kawartha Lakes Road 45. East of Kinmount, Peterborough County and Haliburton County elected to retain Highway 503's route number, although this part of the highway is officially known today as Peterborough Road 503 and Haliburton Road 503. Unless posted otherwise, the speed limit on Highway 503 is 80 km/h (50 mph). Services are available on Highway 48 in Kirkfield, on Highway 35 in Norland, and in both Irondale and Gooderham.