Most of the province's highways comprising the 11,800-kilometre system are broken into one of four main classifications and posted with the appropriate route marker. Even though each of these different types of route designations may have different route markers, they are marked and oftentimes maintained by the Ontario Ministry of Transportation (MTO). Each of these four types of provincial highways are defined below:
King's Highways: Provincial Highways numbered from 3 through 148 (formerly encompassing route numbers 2 through 169) threading throughout the province. There is no standardized system in the numbering of these highways, but some of the "clustering" scheme left over from the early days is still evident. In many places throughout the province, one may have noted that several former highways in a given area began with the same "tens" digit. For example, Former Hwys 73, 74 and 76 through 79 were all clustered in the southwestern part of the province in the London area and to the west. In rare cases these days, a provincial highway may also include a letter "suffix." An "A" suffix usually signifies an alternate route, while a "B" suffix usually denotes a business route into or through the central business district of a mid- to large-size city. However, most of these "suffixed" provincial routes were lost during the downloading sprees of the late-1990s.
400-Series Highways: These highways, which are a specific type of King's Highways, are primarily limited-access freeways, with some exceptions. Since it shares all the characteristics of a 400-Series Highway, the QEW (Queen Elizabeth Way) is grouped here. It, like the 400-Series, is a limited-access freeway, and has been assigned a "secret" 400-series route number. The QEW is signed with a dark blue-on-yellow provincial highway sign with the letters "QEW." For the most part, the 400-Series Highways were not touched in the mass-downloading of highways. The one notable exception is that the QEW now ends at Hwy 427 on the western side of Toronto instead of at the Humber River Bridge, where Hwy 2 and the Gardiner Expressway designation formerly picked up. Also included in the 400-Series section is Hwy 407/ETR. While this route is not a provincially maintained highway, it is numbered in sequence with the provincial highways and is very much related to the rest of the system. Be sure to see Hwy 407's listing for more information on one of Ontario's, and Canada's, more unique highways.
Secondary Highways: Secondary highways, now numbered 502 through 673 (formerly 500 through 673), now exist only in the northern areas of the province, connecting towns and other remote areas to provincial highways. The Secondary Highway system made its debut in the province in 1955-56. For the most part, the Secondary Highways which used to run through Counties and Regional Municipalities in the central and southern part of the province have been downloaded to the local governments. Those, however, in northern Ontario have been retained with a few exceptions as noted above. While all primary (King's) highways in the province are hard-surfaced (paved), not all Secondary Highways are. Many kilometres of Secondary Highways in more remote areas are still gravel surfaced and will likely remain so in light of the massive upheval in the provincial highway system as of late. One final note: in popular useage, all of these Secondary Highways are referred to as just "Highways." In these listings, the abbreviation "Sec Hwy nnn" denotes "Secondary Highway" to distinguish it from the Primary Highways (3-148 plus the 400-Series and QEW).
Tertiary Highways: Tertiary highways, numbered in the low 800s (801-811), are located exclusively in Northern Ontario. Tertiary routes usually connect small communities and remote areas not served by Secondary Highways. In some instances, Tertiary Highways, which have existed since 1962, are extensions of Secondary Highways into more remote areas. These routes often do not end at a community or another highway. Rather they will end suddenly at a lake, river or other feature. Another difference from other highway types, tertiary highways are largely loose-surfaced (gravel) with only one exception to that rule (Ter Hwy 804). These routes were largely spared removal from the provincial highway system since they exist only in northern reaches of the province. It is uncertain, however, what will become of these highways in the future. One final note: in popular useage, all of these Tertiary Highways are referred to as just "Highways." In these listings, the abbreviation "Ter Hwy 8nn" denotes "Teritary Highway" to distinguish it from the Primary and Secondary Highways.
County/Regional Roads: While not a part of the provincial highway system, and therefore not catalogued here, the county and regional road systems have absorbed most of the thousands of kilometres of highways which have been downloaded onto the local governments. Ontario is unique among all Canadian provinces in that it is the only one which actually has a county/regional road configuration. While New Brunswick, Nova Scotia and Manitoba, to name three, have secondary highway systems, these systems are much the same as Ontario's Secondary Highways in the northern parts of the province. As for the county/regional road shield, the motorist can usually count upon the familiar "flowerpot"-style marker, shown at left. What does change, though, are the colours used inside the marker. Many jurisdictions used the standard "black-on-white" style, while some have"yellow-on-green" or "white-on-green" stylizations.
Tourist Routes & Great Lakes Circle Tours: The Ministry of Transportation formerly posted a variety of "Tourist Routes" throughout the province, as well as portions of the Great Lakes Circle Tours. While these are not official route designations in the sense of highway numbering, these routes may still be encountered by travellers along Ontario's highways. These routes are listed in the Other Ontario Highways page. An important note to consider, however: Many of these "Tourist Routes" have been effectively abandoned as large portions of them now run along county, regional, and local roads that were formerly part of the provincial highway system. While some of these routes are continuing to be signed by the local authorities, many are not. Please use caution when attempting to follow these routes!