 Highway 16 | ||||
|---|---|---|---|---|
 Highway 16 highlighted in red | ||||
| Route information | ||||
| Maintained by Ministry of Transportation of Ontario | ||||
| Length | 3.6 km[1] (2.2 mi) | |||
| Major junctions | ||||
| South end |  County Road 2 – Johnstown | |||
 Highway 401 – Edwardsburgh/Cardinal | ||||
| North end |  Highway 416 – Edwardsburgh/Cardinal | |||
| Location | ||||
| Country | Canada | |||
| Province | Ontario | |||
| Counties | Leeds and Grenville | |||
| Highway system | ||||
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King's Highway 16, commonly referred to as Highway 16 and historically as the Prescott Highway, is a provincially maintained highway in the Canadian province of Ontario. The highway once travelled from near Prescott to Ottawa, traversing the distance between the St. Lawrence River and the Ottawa River. However, its length was truncated significantly when most of the route was twinned with a second roadway, and renumbered as Highway 416. A short stub remains through Johnstown, providing access to the Ogdensburg–Prescott International Bridge across the St. Lawrence River to Ogdensburg, New York, where New York State Route 812 continues south.
The Ottawa–Prescott Road, designated in 1918, was one of the first three highways designated in Ontario. By the time the route was numbered as Provincial Highway 16 in August 1925, it was mostly paved, except for portions south of Kemptville, which were paved by 1930. It immediately became the primary route between Toronto and Ottawa, via Highway 2, and as such saw many improvements and realignments carried out over the next three decades. In the 1960s, plans arose for a controlled-access highway to connect Highway 401 with Ottawa, which resulted in the construction of a complete realignment of Highway 16 north of Johnstown. This two-lane highway, known as Highway 16 New, was built between 1969 and 1983; enough land was purchased to build a second two-lane roadway to twin the highway. The twinned roadway was completed between 1989 and 1999, after which the route was renumbered with a 400-series designation.
Former portions of Highway 16 can be followed north from Johnstown, through Spencerville and Kemptville to the Rideau River along Leeds and Grenville County Road 44. Beyond the River it followed Ottawa Road 5 to North Gower, and thereafter Ottawa Road 73 (Prince of Wales Drive) into downtown Ottawa.