King's Highway 2A, commonly referred to as Highway 2A, was the designation of five separate provincially maintained highways in the Canadian province of Ontario. Highway 2A was an alternate route to Highway 2 in Chatham, London and Cornwall; these routes were all eventually redesignated. Highway 2A was also a highway that extended from Windsor to Tilbury, which was redesignated as Highway 98 in 1938.
The final and most familiar section of highway to be designated Highway 2A was the bypass of Highway 2 between Toronto and Newcastle, most of which became part of Highway 401 in July 1952. The short stub of dual carriageway feeding into a new alignment of Kingston Road with Highway 401 was renumbered 2A in 1956 with the completion of the Toronto Bypass. Despite losing its provincial highway status in 1998, Highway 2A was never renamed and is now part of Toronto's municipal expressway system. The speed limit is , and it is patrolled by the Toronto Police Service.
Windsor–Tilbury
The Windsor to Tilbury section of Highway 2A originally was designated in 1929 along the route of what would become Highway 114, near Maidstone. When Highway 18 was redesignated between Windsor and Leamington in 1931, Highway 2 was rerouted onto its former routing. The old routing of Highway 2 prior to that became Highway 2A, and the existing Highway 2A was renumbered as Highway 3B.
Between 1931 and 1938, the route followed the Provincial Highway between Tecumseh Road in downtown Windsor, and Mill Street in Tilbury, both at junctions with Highway 2. In 1938, the entire route was renumbered as Highway 98
Chatham
Highway 2A in Chatham was established in 1957 along the original route of Highway 2 when it was rerouted along the West Chatham Bypass (Keil Street) and Grand Avenue. The route began at Highway 2 at the intersection of Richmond Street and Keil Street, following the former into downtown Chatham, where it turned north onto Queen Street then east onto School Street. From there, the route turned north onto Centre Street, which becomes 5th Street shortly thereafter. The route crossed the Thames River, north of which it became Thames Street and continued to Highway 2 (Grand Avenue East). The route was renumbered as Highway 2B in 1961 and decommissioned by 1970.
Cornwall
Highway 2A (Alt.) in Cornwall was a short-lived designation applied along Nine Mile Road (now Power Dam Drive) and Second Street on the west side of the city. It provided an alternate bypass to the Seaway International Bridge. The route was established in 1965 and remained in place for only two years before being decommissioned in 1967.
London
Highway 2A in London provided an alternative parallel route to Highway 2 through the downtown core, travelling from a concurrent Highway 2 and Highway 4 eastward along Stanley Street, York Street, Florence Street and finally Highbury Avenue. At its eastern end, it met Highway 2 (Dundas Street). The route was established in 1956 and decommissioned in 1968.
Toronto–Newcastle
The Toronto section of Highway 2A is the only one of the five iterations that is still evident and in use today. Although it is no longer provincially maintained, it is still referenced by its highway designation on signage.
As automobile use in southern Ontario grew in the early twentieth century, road design and construction advanced significantly. Following frequent erosion of the former macadamized Lake Shore Road, a cement road known as the Toronto–Hamilton Highway was proposed in January 1914. By November 1914, the proposal was approved, and work began quickly to construct the road from Toronto to Hamilton known today as Lake Shore Boulevard and Lakeshore Road. The road was formally opened on November 24, 1917, wide and nearly long. It was the first concrete road in Ontario, as well as one of the longest stretches of concrete road between two cities in the world.
Over the next decade, vehicle usage increased substantially, and by 1920 Lakeshore Road was again highly congested on weekends. In response, the Department of Highways examined improving another road between Toronto and Hamilton. Middle Road, a continuation of Queen Street west of the Humber River, was chosen to avoid delays on Dundas or Lakeshore. The road was to be more than twice the width of Lakeshore Road at , and would carry two lanes of traffic in either direction. Construction on what was then known as the Queen Street Extension (not to be confused with The Queensway) between Highway 10 and Highway 27 began in early 1931, and between Highway 27 and the Humber River on November 1, 1931.