Wikipedia:WikiProject U.S. Roads/Idaho/All-time list
Sources include:
- 1937 Rand McNally (anything on this map through 39 is marked 1930s; a 1932 Montana map shows numbers through 33, but not 47, and the original clustering is assumed to stop with 39)
- 1939 Rand McNally
- 1940 Rand McNally
- 1946 Rand McNally (smaller scale, some routes missing)
- official maps back to 1947
- 1956 Gousha
- meeting minutes back to 1951
- traffic flow maps back to 1959
- county maps back to 1962
Years before 1951 are therefore not the exact year a change was made.
In 1953 a number was assigned to every unnumbered state highway, but these don't seem to be listed in one place. At the same time, duplicate numbers were changed. A year of 1953 below means that it was probably numbered then.
| from | to | notes | |
|---|---|---|---|
| SH 1 | 1930s | now | |
| SH 3 | 1929 | 1940 → US 10A | |
| SH 3 | 1953 | now | |
| SH 4 | 1929 | now | |
| SH 5 | 1929 | now | |
| SH 6 | 1929 | now | |
| SH 7 | 1929 | now | |
| SH 8 | 1929 | now | |
| SH 9 | 1929 | 1962-07 → US 12 | |
| SH 9 | 1965-08 ← 7 (part) |
now | |
| SH 10 | 1953 | 1953 → 62 |
number appears on 1953 map; added in 1953-07 (Kamiah-Green Creek Highway) |
| SH 11 | 1929 | now | |
| SH 12 | 1929 | 1962-07 → 64 | |
| SH 13 | 1929 | now | |
| SH 14 | 1929 | now | |
| SH 15 | 1929 | 1967-09 → 55 (part) | |
| SH 16 | 1929 | now | |
| SH 17 | 1929 | 1960-10 | started as Banks to Stanley; ended up only to Crouch |
| SH 18 | 1929 | 1940 → US 20 (part) |
Parma to Caldwell |
| SH 18 | 1953 | 1975-12 | west from Parma |
| SH 19 | 1929 | now | |
| SH 20 | 1929 | 1950 → 72 | |
| SH 21 | 1929 | now | |
| SH 22 | 1929 | now | |
| SH 23 | 1929 | 1940 → US 93A (part) |
Shoshone to Carey |
| SH 23 | 1953? ← 22 (part) |
1971-12 | Bellevue to Carey; east of Picabo became part of 68 earlier |
| SH 24 | 1929 | now | |
| SH 25 | 1929 | now | |
| SH 26 | 1929 | 1953 → 74 | |
| SH 27 | 1929 | 1941 → US 93A (part) |
US 20 had replaced Arco to Blackfoot on 1941 Montana map; the rest of 27 became US 93A in 1942 |
| SH 27 | 1950 | now | |
| SH 28 | 1929 | now | |
| SH 29 | 1929 | 1937 → 22 (part) | |
| SH 29 | 1938 ← 22 (part) |
1950 → US 26 (part) |
22 had moved on 1938 Montana map |
| SH 29 | 1953 | now | appears on 1955 Montana map |
| SH 31 | 1929 | 1934 | seen on 1929 Montana map; later 287, and now 87 |
| SH 31 | 1934 | now | |
| SH 32 | 1929 | now | |
| SH 33 | 1929 | now | became US 20A from 1944-1953 |
| SH 34 | 1929 | now | |
| SH 35 | 1929 | 1939 → US 89 |
southwest of Geneva why is this labeled on the 1953 map? |
| SH 35 | 1953 | 1962-09 | Utah to Red Rock Pass |
| SH 36 | 1929 | 1937 → US 191 (part) | |
| SH 36 | 1962-12 | now | |
| SH 37 | 1929 | now | |
| SH 38 | 1929 | 1960-09 | removed 1955-10 in Bannock County |
| SH 38 | 1985-10? ← 37 (part) |
now | |
| SH 39 | 1929 | now | |
| SH 40 | 1929 | 1939 → US 89 (part) |
north of Geneva; did not include current 61 |
| SH 40 | 1972-09 | now | |
| SH 41 | 1934 | now | |
| SH 42 | 1934 | 1965-08 → 3 (part) |
Spalding to Kendrick (originally continued to Harvard on what became 7 ca. 1953) |
| SH 43 | 1934 | 1940 | Ahsahka to Kendrick unlabeled on 1947 and 1950 maps; part of 7 in 1953 |
| SH 43 | 1953 (ca.) ← 7 (part) |
1965-08 → 3 (part), 8 (part) |
Mashburn to Elk River still part of 7 on 1950 map; 43 on 1953 map |
| SH 43 | 1978-12 ← US 191 (part) |
now | |
| SH 44 | 1934 | now | |
| SH 45 | 1934 | now | |
| SH 46 | 1935 | now | |
| SH 47 | 1935 | 1957-10 | |
| SH 47 | 1958-09 ← US 20-191 (part) |
now | |
| SH 48 | 1935 | now | |
| SH 49 | 1937 | 1940 → US 20 (part) |
west of US 95 |
| SH 49 | 1953 | 1962-09 | Idaho Falls to Menan portion at south end removed in 1957-11 |
| SH 50 | 1938 | now | |
| SH 51 | 1938 | now | |
| SH 52 | 1938 | now | |
| SH 52A | 1953 | 1973-12 | northwest of Emmett; had been part of 52 |
| SH 53 | 1938 | now | |
| SH 54 | 1953 | now | |
| SH 55 | 1953 | 1955-10 | Colburn-Culver Road |
| SH 55 | 1967-09 ← 15, 72 |
now | |
| SH 56 | 1953 | 1955-10 | Sagle-Midas Road |
| SH 57 | 1953 | now | |
| SH 58 | 1953 | now | not a state highway on 1953 map, but Worley West Road is mentioned in 1953 |
| SH 59 | 1953 | when? | where was 59 in 1953? Probably south from Good Grief |
| SH 60 | 1953 | when? | where was 60 in 1953? Probably Thain Road (removed 1953-07) |
| SH 60 | 1959-09 | now | |
| SH 61 | 1953 | now | |
| SH 62 | 1953 ← 10 |
now | |
| SH 63 | 1953 | when? | where was 63 in 1953? Probably east from Orofino |
| SH 64 | 1953 | when? | where was 64 in 1953? Probably Kuna-Nampa |
| SH 64 | 1962-07 ← 12 |
now | |
| SH 65 | 1953 | when? | where was 65 in 1953? Probably Kuna-Regina |
| SH 66 | 1953 | now | |
| SH 67 | 1953 | now | not a state highway on 1953 map, but road is mentioned in 1952 |
| SH 68 | 1953 ← 22 (part) |
1971? → US 20 (part) |
mentioned in 1954 as "old State Highway 22, new number 68" official maps show it becoming US 20 between 1970 and 1972, but minutes continue to call it 68 through 1978 |
| SH 69 | 1953 | now | |
| SH 70 | 1953 | 1977-04 | northwest from Weiser |
| SH 71 | 1953 | when? | where was 71 in 1953? Probably New Plymouth Spur |
| SH 71 | 1956-10 | now | |
| SH 72 | 1953 ← 20 |
1967-09 → 55 (part) |
first mentioned in 1954 |
| SH 72 | 1972-11?? ← US 30 (part) |
now | |
| SH 73 | 1953 | 1953-11 | Buhl-Castleford Highway |
| SH 73 | 1965 | 1972-11?? → US 30 (part) |
south from New Plymouth |
| SH 74 | 1953 ← 26 |
now | mentioned in 1954; originally included the Blue Lakes Spur |
| SH 75 | 1953 | 1977-02 | Ketchum to Sun Valley; extended to Chilly in 1960-11; seems to have been cut back in 1973-1974; became a spur of 75 when US 93 was moved |
| SH 75 | 1977-02 ← US 93 (part) |
now | 1976-12 says that AASHTO had just approved the change. Signs were scheduled to be changed on January 1, 1978 |
| SH 76 | 1953 | 1954-12 | Richfield Spur |
| SH 77 | 1953 | now | |
| SH 78 | 1972-11 | now | |
| SH 78 | 1953 | when? | Caldwell-south |
| SH 79 | 1953 | now | |
| SH 80 | 1953 | 1962-07 | Menan to Lorenzo |
| SH 81 | 1970-12 ← US 30S (part) |
now | where was 81 in 1953? Probably Idaho Falls-Ammon (removed 1953-01) |
| SH 82 | never? | never? | where was 82 in 1953? Probably Gimlet-East |
| SH 83 | never? | never? | where was 83 in 1953? Probably Gannett-West |
| SH 84 | 1953 | 1977-11 | Started out Spencer to Macks Inn; extended to Big Springs in 1957-10 and west section removed by then |
| SH 85 | never? | never? | where was 85 in 1953? Probably Shelley-North |
| SH 86 | 1953 | 1964-10 | Dayton to Preston; now part of 36 |
| SH 87 | never? | never? | where was old 87? |
| SH 87 | 1967-05 ← 287 |
now | |
| SH 88 | 1958-05 | 1977-02 → 33 (part) |
Howe to Rexburg |
| SH 90 | never? | never? | Payette to Oregon? |
| SH 92 | never? | never? | |
| SH 94 | never? | never? | |
| SH 96 | 1959-10 | 1960-09 → 287 | |
| SH 97 | 1977-05? ← US 95A (part) |
now | |
| SH 99 | 1961-02 | now | |
| SH 128 | 1989-08 | now | |
| SH 162 | 1993?? ← 62 (part) |
now | |
| SH 167 | 2010 (ca.)? ← 67 (part) |
now | |
| SH 200 | 1967 or 1968 ← US 10A |
now | |
| SH 287 | 1960-09 ← 96 |
1967-05 → 87 |
MT 287 was temporarily rerouted after the 1959 Yellowstone earthquake |