Previously: ON 8A (1925-32), ON 20 (1932-64); diversion around Confederation Park excepted.

Previously: ON 5 (1925-27; south of Arkledun Ave.)

Concurrent with: ON 6. "106" was an internal designation used to refer to a portion of the highway covered by municipal maintenance, and would never have been signed in the field.

Due to a one-way split, the northern extremity of RR 106 encompassed southbound traffic only while northbound traffic was carried by RR 178.

Concurrent with: ON 8. "108" was an internal designation used to refer to a portion of the highway covered by municipal maintenance, and would never have been signed in the field.

Much of Main Street follows Concession Line 3. Due to a one-way split, the northern extremity of RR 108 encompassed eastbound traffic only while westbound traffic was carried by RR 112.

Succeeded by: RR 8 (east of Cootes Dr.)

Concurrent with: ON 8 (west of Kensington Ave). "112" was an internal designation used to refer to a portion of the highway covered by municipal maintenance, and would never have been signed in the field.

Succeeded by: RR 8 (west of Kensington Ave.)

Previously: ON 8A (1925-32), ON 20 (1932-64).

Much of this road follows Concession Line 6.

Previously: RR 51 (1950s). Follows Concession Line 8.

Follows Concession Line 5.

A short connector between other roads.

Previously: ON 20 (1930-32), ON 20A (1932-37), ON 55 (1937-49); Concession segment only. This road followed Concession Line 4; hence the name.

Adjustments: A portion of Mud Street was bisected by the Red Hill Valley Parkway in the 2000s, leaving a discontinuity. (Of course, by that point the three-digit numbering system had long gone defunct.)

Previously: ON 2 (York west of Dundurn Street), ON 6 (York west of Bay Street).

Previously: ON 20A (1938-51), ON 55 (1957-61); portion east of Kenilworth or Beach Road only.

Largely follows Concession Line 2. Due to a one-way split, the central portion of RR 138 encompassed eastbound traffic only while westbound traffic was carried by RR 149. The elevated east portion of the highway is now named Nicola Tesla Boulevard.

Previously: ON 102 (1947-1964).

Succeeded by: RR 8, which is still in commission today.

Previously: RR 45. Street name also given as Gray Rd; no consistency.

Concurrent with: ON 2. "147" was an internal designation used to refer to a portion of the highway covered by municipal maintenance, and would never have been signed in the field.

Concurrent with: ON 53. "153" was an internal designation used to refer to a portion of the highway covered by municipal maintenance, and would never have been signed in the field.

Rymal Road also follows the baseline separating historical Barton Township from Glanford.

Previously: RR 31 (1950s).

Previously: ON 20 (1930-32), ON 20A (1932-37), ON 55 (1937-61)

Previously: ON 55 (1949-58)

Previously: RR 48 (1950s)

Previously: The Jolley Cut was used by a multitude of highways at some point or another, including ON 5 (west of Claremont Access, 1925-27), ON 6 (west of Claremont Access, 1927-70s), ON 20 (1930-32), ON 20A (1932-37), and ON 55 (east of Claremont Access, 1937-49).

Previously: ON 20A (north of Main St., 1947-51), ON 55 (1957-61)

Previously: ON 20A (1938?-46, portion from Beach Rd. to Main St.)

Concurrent with: ON 6 (south of King St).

Previously: ON 6 (between Jackson and Wellington, 1948-57)

Previously: ON 5 (south of Main, 1925-27), ON 6 (south of Main, 1927-48; south of Young, 1948-57; south of King, 1957-70s)

Previously: ON 6 (south of King, 1957-70s)

Previously: ON 6 (1957-70s)

Concurrent with: ON 2 and ON 8. "185" was an internal designation used to refer to a portion of the highways covered by municipal maintenance, and would never have been signed in the field.

Succeeded by: RR 8, which is still in commission today.

Concurrent with: ON 2 and ON 8 (north of Main St.)