Ontario Highway 40 History - The King's Highways of Ontario

King's Highway 40 is a major trunk highway which links Highway 401 south of Chatham to Highway 402 in Sarnia. The highway traverses a mostly rural portion of Southwestern Ontario. The only major town along the highway between Chatham and Sarnia is Wallaceburg, which is situated roughly at the half-way point along Highway 40 between the two cities. The history of Highway 40 dates back to the mid-1930s, when the Department of Highways of Ontario (DHO) assumed a new King's Highway through Kent and Lambton Counties. Preliminary Route Plans were prepared in February 1934, showing the proposed route of the new King's Highway in Kent and Lambton Counties. The highway began at the Highway 2 Junction in Chatham and headed northwesterly to Wallaceburg. After a brief turn to the west, the new highway followed the St. Clair River northerly to join with Highway 7 in Sarnia. The DHO acquired the section of the new route within Kent County on March 28, 1934 and the section within Lambton County on May 2, 1934. Sections of the road passing through Chatham, Wallaceburg, Courtright and Sarnia were not assumed by the DHO and thus those sections of the route remained under municipal jurisdiction. The new King's Highway was designated as Highway 40. Originally, the highway was 50 miles (81 km) in length (See Map).

At the time of the route's assumption in 1934, Highway 40 was already paved between Chatham and Wallaceburg. The remainder of the highway from Wallaceburg to Sarnia was gravel-surfaced. Paving work was carried out through the villages on Highway 40 from Wallaceburg to Sarnia in 1936. Paving work was completed between Wallaceburg and Sombra and from Corunna to Sarnia in 1937. Paving was completed between Sombra and Courtright in 1942. Paving work was completed on Highway 40 in 1943, when the last gravel section between Courtright and Corunna was paved over.

In 1963, a new bypass road was assumed by the DHO around Sarnia. This bypass road would intercept traffic on Highway 40 before it entered Sarnia and provide a limited-access route around the city for through traffic wishing to access Highway 402. The Sarnia Bypass Road was assumed as a new King's Highway on May 1, 1963 and was designated as Highway 40A on June 27, 1963. The new Sarnia Bypass was opened to traffic on October 25, 1963. In 1965, Highway 40 was rerouted onto the Sarnia Bypass, replacing the Highway 40A designation. The old alignment of Highway 40 through downtown (via Christina Street, Vidal Street and Front Street) became Highway 40B.

The completion of Highway 401 through Southwestern Ontario put increased traffic pressure on the two county roads leading from Highway 401 into Chatham (Bloomfield Road and Communication Road). The DHO assumed Communication Road (Kent County Road 11) south of Chatham as a new King's Highway in 1967. The new route was assumed on December 5, 1967, and designated as a King's Highway with an unposted "7000-Series" designation (Highway 7089) on December 14, 1967. The new highway began at the east limits of Chatham at the end of Park Avenue and then turned south via Communication Road out to Highway 401. The route of Highway 7089 was extended south from Highway 401 in 1970, when the section of Kent County Road 11 between Highway 401 and Blenheim was assumed as a King's Highway. The section of Communication Road running through Blenheim was not assumed by the DHO. The DHO assumed the south section of Communication Road on April 15, 1970, and designated the route as part of Highway 7089 on May 21, 1970. At some point during 1970, the route of Highway 7089 was renumbered as Highway 40. Communication Road is marked as Highway 40 on the 1971 Edition of the Official Road Map. However, the 1970 DHO Mileage Table lists the southern terminus of Highway 40 as Blenheim, along with a revised highway length of 68.4 miles.

During the 1970s, significant changes were made to the route of Highway 40. In 1972, construction began on a major realignment of Highway 40 between Wallaceburg and Sarnia. The old highway was bypassed by a more direct through route, located roughly 5 km further inland from the St. Clair River. The new route of Highway 40 was completed between the Sarnia Bypass and the Highway 80 Junction in the Fall of 1975. Construction of the next section, from Highway 80 southerly to County Road 2 to Sombra, began in 1974. Construction of the next section, from County Road 2 to Highway 40 near Wallaceburg, began in 1976. Both sections of New Highway 40 from Highway 80 to the Highway 40 Junction at Wallaceburg were completed in 1977. For a brief period from 1975 to 1977, Highway 40 & Highway 80 shared a short concurrent route east of Courtright. Parts of the New Highway 40 were constructed as a four-lane divided highway. The highway's length after New Highway 40 opened was 103 km. Roughly 44 km of the old highway along the St. Clair River had been bypassed by New Highway 40. The old highway was decommissioned from the Sarnia City Limits to County Road 2 in Sombra on October 17, 1979. The section of Old Highway 40 from Walpole Island to the Lambton-Kent County Boundary was decommissioned on October 2, 1981, while the section of Old Highway 40 from the Lambton-Kent County Boundary to County Road 2 in Sombra was decommissioned shortly thereafter, on October 11, 1981. The final section of Old Highway 40 between Walpole Island and the New Highway 40 Junction near Wallaceburg was decommissioned on December 22, 1984.

A small change was made to the route of Highway 40 in Chatham in 1994-1995. As originally assumed in 1967, the highway turned west from Communication Road along Park Avenue. This route meant that all through traffic heading for Highway 40 north of Chatham was sent through the City Centre. It was decided that Highway 40 should be extended north along Communication Road from Park Avenue to Highway 2 (Grand Avenue), in an effort to keep through traffic away from Downtown Chatham. The new Highway 40 along Communication Road was designated as a Controlled Access Highway (CAH) on March 14, 1995. The old route of Highway 40 leading into Chatham via Park Avenue was decommissioned on October 27, 1994. Highway 40 was routed concurrently with Highway 2 along Grand Avenue into Chatham, where Highway 40 resumed its route north towards Wallaceburg. The new route of Highway 40 was a significant improvement over the original route of Highway 40 through Downtown Chatham. On January 1, 1998, the southernmost section of Highway 40 from the Highway 401 Interchange southerly to the Highway 3 Junction in Blenheim was downloaded to the Municipality of Chatham-Kent. This section of Highway 40 is now known as Chatham-Kent Road 11. The post-1998 length of Highway 40 is now 92 km.

Most sections of Highway 40 are two lanes, but there are some undivided four-lane sections through towns along the route. From Rokeby Line to Indian Road in Sarnia, Highway 40 is a four-lane divided highway. A short section of divided highway also exists at the northern end of Highway 40 where it connects to Highway 7 (now Lambton Road 22) and Highway 402. Services along Highway 40 are quite scarce outside of towns. The speed limit on Highway 40 is 80 km/h (50 mph), unless posted otherwise. Please visit the Highway 40 Mileage Chart page for a list of mileage reference points along Highway 40.