List of former Ontario provincial highways

Ontario, Canada, has an extensive network of Primary (King's), Secondary, and Tertiary Highways, with county-level and city-level roads linking between them. Over the years, however, Ontario has turned back highways to the local authorities, renumbered them, or upgraded them to 400-series highways.

In 1997 and 1998, many sections of the provincial highway network were downloaded to local municipalities (such as cities, counties or regional municipalities) by the Ontario Ministry of Transportation as a cost-saving measure. While highways were occasionally transferred to local governments in the past, the 1997-1998 downloads represented the most significant changes to Ontario's highway network. Many highways were completely devolved, while of others only short sections remain under provincial jurisdiction (Highway 2, once stretching across Southern Ontario, now is only a few kilometres long). Below is a partial list of partially or wholly devolved highways since 1997.

Primary highways

• Highway 2 – Windsor to the Ontario-Quebec boundary, now Lake Shore Boulevard, Kingston Road, Toronto Road, and Loyalist Road. Its purpose was largely superseded by Highway 401; only a 4.4 kilometre section near Gananoque remains.
• Highway 2A – Scarborough, Ontario. Was once an expressway in the 1940s until Highway 401 took over its current route in 1952.
• Highway 2A (Essex County, Ontario) (1929)
• Highway 3 – between St. Thomas and Leamington.
• Highway 4 – Downloaded portions: south of the interchange with Highway 401, and north/east of Highway 8
• Highway 5
• Highway 6 – Downloaded portions: south/west of Port Dover, Ontario
• Highway 7 – Downgraded the portion in York Region west of Main St. Markham/ Markham Rd./ Highway 48.
• Highway 8
• Highway 9
• Highway 10 – now Hurontario Street in Mississauga, Ontario, and Main Street in Brampton, Ontario.
• Highway 11 – from Barrie southward; primarily known as Yonge Street nowadays
• Highway 11A – Toronto; Gardiner Expressway/Lake Shore Boulevard to Macdonald-Cartier Freeway (ON-401) now known only as, York Street then University Avenue, Avenue Road, and Oriole Parkway.
• Highway 11B – Cobalt-New Liskeard. Portions of the road in Coleman Township are still signed as 11B.
• Highway 12 – Whitby--south of Highway 407 right of way.
• Highway 14 – Marmora to Highway 62 near Foxboro.
• Highway 15 – re-routed onto part of Highway 29's former routing.
• Highway 16 – Upgraded to a 400 series highway (Highway 416). Now Only a short stub remains.
• Highway 17 – Replaced by Highway 417 east of Arnprior
• Highway 17 – From Windsor to Leamington, now Essex County Road 20
• Highway 19 – From terminus at Port Burwell to Highway 3 in Tillsonburg; From Highway 401 to terminus at Highway 86 near Milverton. The section from Tillsonburg to Highway 401 remains.
• Highway 20 – QEW exit 88 E of Hamilton to QEW/ON-420 interchange, now Confederation Parkway, through Stoney Creek, Rymal Road, and Lundy's Lane.
• Highway 21 – Portions South of Highway 402
• Highway 22 – London, Ontario to near Warwick, Ontario, connecting to Sarnia, Ontario and to Arkona by Highway 7; replaced by most of routing of Highway 402
• Highway 24 – 2 km south of Cambridge and northward through Guelph, Orangeville, Shelburne, and Collingwood on Georgian Bay.
• Highway 24A
• Highway 25 – Now Bronte Road (south of Highway 407 (Ontario) in Oakville), Ontario St/Steeles Av/Martin St/Halton Regional Rd 25 in Milton, Halton Regional Rd 25 in Halton Hills, and Main Street in Acton. Continues in segments through Wellington & Dufferin Counties to north of Grand Valley at Highway 89.
• Highway 27 – Etobicoke to Midhurst; now referred to as Highway 27 in Toronto, York Regional Road 27 in Vaughan, and Simcoe County Road 27 in Simcoe County
• Highway 28 – Port Hope to Highway 7A, (which had a concurrency with Highway 115 for 13 km to the Parkway exit), up to NE of Lakefield, at Highway Highway 134.
• Highway 29 – Brockville to Arnprior
• Highway 30 – Brighton to Havelock
• Highway 31 – Morrisburg to Ottawa
• Highway 32 – Gananoque to Seeleys Bay
• Highway 33 – Trenton to Picton
• Highway 34 – Lancaster to Hawkesbury
• Highway 36 – Lindsay to Highway 28 at Burleigh Falls.
• Highway 38 – Kingston to Highway 7 near Sharbot Lake; now referred to as Road 38
• Highway 39 – Windsor to south of Belle River. (1934-1970. Now Essex County Road 22 from Essex County Road 42 to Essex County Road 2, and Essex County Road 2 into Windsor. Rendered obsolete with the completion of E.C. Row Expressway in 1970, and was absorbed into Highway 2.
• Highway 42 – Westport to Forthton.
• Highway 43 – Perth to Alexandria, via Smiths Falls, and Winchester deleted in 1998--Perth to Smith Falls section was Highway 15 prior to completion of Highway 7 in 1950s.
• highway 44 – Highway 15 in Almonte, Ontario to Highway 17 west of Carp, Ontario (1938-1997)
• Highway 45 – Cobourg to Norwood.
• Highway 46 – from Ontario Hwy 7 to Victoria County Rd. 48 near Bolsover. Now Victoria County Rd. 46.
• Highway 47 – Highway 48 north of Stouffville to Highways 7 & 12 south of Greenbank.
• Highway 48 – Between Kingston Road and York Regional Road 73.
• Highway 49
• Highway 50 – Toronto section; also referred to as Albion Road to Highway 89 west of Alliston.
• Highway 51 – North of Cataract to Caledon.
• Highway 52 – East of Alberton to Highway 8 at Peters Corners.
• Highway 53 – Stoney Creek to Eastwood.
• Highway 54
• Highway 55
• Highway 56 – Highway 3 west of Canfield to Stoney Creek.
• Highway 59
• Highway 68 – became Highway 6 on Manitoulin Island.
• Highway 69 – replaced by Highway 400 south of MacTier
• Highway 70 – renamed Highway 6 from Hepworth to Springmount.
• Highway 73 – Port Bruce, Ontario to Dorchester, Ontario
• Highway 74; New Sarum to Nilestown. Deleted in 1997.
• Highway 76
• Highway 78
• Highway 79
• Highway 80
• Highway 81
• Highway 82
• Highway 83
• Highway 84
• Highway 87
• Highway 88 – Highway 27 junction at Bond Head to Highway 11 junction in Bradford. Existed from 1938 to 1998. Renamed as Simcoe County Road 88.
• Highway 89
• Highway 90 – Barrie to Angus and CFB Borden.
• Highway 93 – South of Highway 400 interchange
• Highway 95 – Wolfe Island
• Highway 96 – Wolfe Island
• Highway 97 – Freelton to Hickson, through Galt/Cambridge.
• Highway 98 – Essex County 1938-1970. It was deleted, becoming Essex County Road 46, and Kent County (now Chatham-Kent) Road 8. Its western terminus was downtown Windsor, and its eastern terminus was downtown Blenheim, at Highways 40 and 3. Rendered obsolete with the completion of nearby freeway, Highway 401 (which paralleled Highway 98 for the majority of its length).
• Highway 99 – Governor's Road (original alignment of Dundas Street from Highway 24 North of Brantford to Ancaster
• Highway 100 – MCF (ON-401) at exit 194 to Former ON-2, eastern part of London, now Veterans Memorial Parkway.
• File:Ontario 103.png Highway 103 – Highway 400 and 12 to Highway 69 junction, first the original alignment of Highway 69, now Highway 400.
• File:Ontario 104.png Highway 104 – to Grand Valley from Highway 9, then Highway 25.
• Highway 107 – Highway 18 in Ruthven, Ontario, to Highway 3 in Ruthven. Now Essex County Road 45.
• Highway 114 – Highway 3 (Former alignment, now Essex County Road 34) in Maidstone, Ontario (now a part of Tecumseh, Ontario, to Highway 98 (Now Essex County Road 46). Part of road is still signed as "Old HWY 114" from Manning Road (Essex County Road 19) to Provincial Road (Essex County Road 46).
• Highway 117 – Highway 11 north of Bracebridge to Dorset.
• Highway 118
• Highway 121 – Highway 35 south of Fenelon Falls to Haliburton. Eastward is renamed Highway 118.
• Highway 126– MacDonald-Cartier Freeway (Highway 401) in the south end of London, Ontario (partially superhighway--Wenige Expressway) to Highway 2, some think extended to Highway 22 (present Fanshawe Park Road East), now known as Highbury Avenue. (The part between Highway 401 and the south Thames River had no name, while a half-mile section from the Thames to Hamilton Road was the Wenige Expwy, and north from there was Highbury Avenue.)
• Highway 131 – Renamed Simcoe County Road 27.
• Highway 134 – Renamed Highway 28 when that road was re-routed and fully absorbed Highway 134.
• Highway 135 – Short highway in London, between Highway 401 and former Highways 2 & 4. Now called Exeter Road.
• Highway 136 – Cataract to Orangeville. Formerly Highway 24.
• Highway 148 – Highway 17 to Pembroke, Ontario city limits was decommissioned, now just a connecting link (which allows it to still be signed as Highway 148). Continuation of Quebec route 148.
• Highway 169 – Brechin to Foot's Bay via Gravenhurst, shared space with Highway 11 from Washago to Gravenhurst.

Additional highways and bypass routes devolved: 2B, 2S, 3B, 4A, 5A, 7B, 8A, 11B, 12B, 13, 15A, 16, 17A, 17B, 24A, 35B, 40B, 48B.

Secondary highways

• Highway 517 – Used to run from Boulter to Combermere at Highway 62. Downgraded to County Rd. status in Hastings and Renfrew counties.
• Highway 543 – Highway 69 to Dew Drop Road in Sudbury. Downloaded in 1973 upon the creation of the Regional Municipality of Sudbury as Long Lake Road, part of Regional Road 80. Now designated Greater Sudbury Municipal Road 80.
• Highway 544 – Downtown Sudbury to Cartier. Redesignated as Highway 144 in 1965, as extension to Timmins was under construction.
• Highway 549 – Whitefish to Lake Panache in the town of Walden; downloaded in mid-1980s and now designated as Greater Sudbury Municipal Road 10.
• Boulter Road was an un-numbered secondary highway from at least the 1930s. It was downloaded in 1998, with its more-well-known brother road, Highway 517.
• Highway 550B – Sault Ste. Marie business route linking Highway 550 with the Sault Ste. Marie International Bridge. Returned to original city street names when Ontario decommissioned the B-series highways.
• Highway 646 – Linking Highway 599 with Pickle Lake and Pickle Crow. Now identified on signage as Pickle Lake Road.

Recycling

Highway numbers have even been "recycled" (used more than once on a provincial highway), however the use tends to be as far as possible from the original routing, and generally a few decades' time separate each numbering, to minimize confusion.

• Highway 77 (Ontario)

Highway stubs

This section will list all highways that have lost segments of their routings, are in at least two parts (or in the case of Highway 7 for a while, three parts), or have been truncated short of their original termini. Examples of this are Highway 3, Highway 4 and Highway 7.