Ontario Highway 400 (King's Highway 400)

Ontario Highway 400 is a major north–south controlled-access provincial freeway linking Toronto with central Ontario, serving commuters, freight traffic and access to cottage country over about 226 km.

Overview

King's Highway 400, commonly called Highway 400, is a provincially maintained controlled-access freeway in Ontario. It runs primarily north–south for approximately 226 kilometres (140 miles), connecting the city of Toronto with central and northern parts of the province. The route is part of the 400-series network of high-capacity highways that support long-distance travel and regional commuting.

Route and characteristics

The highway is a divided, multi-lane expressway built to modern freeway standards for most of its length, with grade-separated interchanges and limited access. Southbound segments serve dense urban and suburban traffic near Toronto, while northern stretches pass through rural and recreational areas. Major municipalities and communities served along the corridor include:

Toronto and its northern suburbs
Large regional centres and smaller towns north of the GTA
Access points for recreational regions and cottage country

History and administration

Developed as part of the mid-20th-century expansion of Ontario’s highway network, Highway 400 was created to improve high-speed travel between the provincial capital region and more distant communities. The roadway is administered and maintained by the provincial highway authority, the Ministry of Transportation, and is designated within the provincial King's Highway system as part of the 400-series.

Uses and importance

Highway 400 serves multiple roles: it is a commuter artery for people travelling into Toronto, a freight corridor for trucks moving goods to and from the Greater Toronto Area, and a primary route for tourists and residents accessing lakes, parks and cottages north of the city. Seasonal traffic patterns can vary substantially, with heavier recreational travel in summer months and peak commuter flows on weekdays.

Notable facts and distinctions

As one of Ontario’s principal 400-series highways, Highway 400 is among the busiest provincial freeways in Canada in portions closest to Toronto. Its designation as a King's Highway reflects its status in the provincial network. For reference and mapping information consult provincial resources or transport guides for provincial highways, regional travel advisories in Canada, and local transit or traffic updates available for the Toronto area.

Travelers planning trips along Highway 400 should check current conditions, construction notices and seasonal advisories through official channels to ensure safe and efficient journeys.