# List of U.S. Highways in Colorado

The U.S. Highways in Colorado are the segments of the national United States Numbered Highway System that are owned and maintained by the state of Colorado. The longest of these highways is U.S. Highway 160 (US 160), which spans 497.223 miles (800.203 km) across southern Colorado. The standards and numbering for the system are handled by the American Association of State Highway and Transportation Officials (AASHTO) while the routes in the state are maintained by the Colorado Department of Transportation (CDOT).

## Mainline highways

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| US 6 | 467.284 | 752.021 | I-70/US 6/US 50 near Mack | US 6 near Holyoke | 01931-01-011931 | current | |
| US 24 | 277.319 | 446.302 | I-70 near Minturn | US 24 near Burlington | 01936-01-011936 | current | |
| US 34 | 259.529 | 417.671 | US 40 in Granby | US 34 near Wray | 01939-01-011939 | current | |
| US 36 | 224.718 | 361.649 | US 34 at Deer Ridge in Rocky Mountain National Park | US 36 near Idalia | 01926-01-011926 | current | |
| US 38 | — | — | Greeley | US 38 at the Nebraska state line | 01926-01-011926 | 01931-01-011931 | Became part of US 6 and US 34 |
| US 40 | 486.924 | 783.628 | US 40 west of Dinosaur | US 40 east of Arapahoe | 01926-01-011926 | current | |
| US 40N | — | — | US 40 in Limon | US 40N at the Kansas state line | 01926-01-011926 | 01935-01-01c. 1935 | Became part of US 24 |
| US 40S | — | — | US 40N in Limon | Grand Junction | 01926-01-011926 | 01935-01-01c. 1935 | Became parts of US 24 and US 40 |
| US 50 | 467.583 | 752.502 | I-70/US 6/US 50 near Grand Junction | US 50/US 400 near Holly | 01926-01-011926 | current | |
| US 84 | 27.924 | 44.939 | US 160 near Pagosa Springs | US 84 near Chromo | 01941-01-011941 | current | |
| US 85 | 309.542 | 498.160 | I-25/US 85/US 87 near Trinidad | US 85 near Eaton | 01926-01-011926 | current | |
| US 87 | 298.879 | 480.999 | I-25/US 85/US 87 near Trinidad | I-25/US 87 | 01936-01-011936 | current | Entirely concurrent with Interstate 25 within the state. |
| US 138 | 59.823 | 96.276 | US 6 near Sterling | US 138 near Julesburg | 01926-01-011926 | current | Orphan route. Was a spur of US 38 before it became part of US 6. |
| US 160 | 497.223 | 800.203 | US 160 near Teec Nos Pos, Arizona | US 160 near Walsh | 01930-01-01c. 1930 | current | Original western terminus was Trinidad. Extended via US 85 and US 450 to near Dove Creek in 1934. Rerouted west of Cortez via US 164 in 1970 toward Four Corners Monument. |
| US 164 | 40.290 | 64.840 | US 164 near Four Corners Monument | Cortez | 01964-01-011964 | 01970-01-011970 | Became part of US 160 west of Cortez |
| US 285 | 263.947 | 424.782 | US 285 near Antonito | I-25 in Denver | 01936-01-011936 | current | Originally terminated on Alameda Ave. at US 85/US 87. In 1969, rerouted to terminate at US 40 (Colfax Ave.) in Aurora. Truncated at I-25 in Denver in 1979. |
| US 287 | 385.223 | 619.956 | US 287/US 385 near Campo | US 287 near Virginia Dale | 01935-01-011935 | current | |
| US 350 | 72.718 | 117.028 | US 160 near Walsenburg | US 50 in La Junta | 01926-01-01c. 1926 | current | |
| US 385 | 317.631 | 511.178 | US 287/US 385 near Campo | US 385 near Julesburg | 01958-01-011958 | current | |
| US 400 | 14.814 | 23.841 | US 50/US 385 in Granada | US 50/US 400 near Coolidge, Kansas | 01996-01-011996 | current | Entirely concurrent with US 50 within the state |
| US 450 | — | — | US 450 at the Utah state line | US 85/US 87 in Walsenburg | — | 01939-01-011939 | Now US 491 north of Cortez and US 160 from Cortez to Walsenburg |
| US 491 | 69.602 | 112.014 | US 491 north of Shiprock, New Mexico | US 491 north of Dove Creek | 02003-01-012003 | current | Formerly US 666 |
| US 550 | 130.219 | 209.567 | US 550 near Durango | US 50 in Montrose | 01926-01-011926 | current | |
| US 650 | — | — | — | — | 01927-01-01c. 1927 | 01936-01-011936 | Now SH 291 through Salida and US 285 south of Buena Vista |
| US 666 | 69.602 | 112.014 | US 666 north of Shiprock, New Mexico | US 666 north of Dove Creek | 01926-01-01c. 1926 | 02003-01-012003 | Now US 491 |
| US 789 | — | — | New Mexico state line | Wyoming state line | — | — | Proposed, but never commissioned; would have followed (south to north): US 666, US 160, US 550, US 6/US 24, SH 13 |
| Former ||||||||

## Special routes

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| US 6 Byp. | — | — | — | — | — | — | Served Colorado Junction |
| US 24 Bus. | — | — | Manitou Springs | Colorado Springs | — | — | |
| US 34 Bus. | — | — | — | — | — | — | Serves Estes Park |
| US 34 Bus. | — | — | — | — | — | — | Serves Greeley |
| US 34 Bus. | — | — | — | — | — | — | Served Brush |
| Temp. US 40 | — | — | Steamboat Springs | Kremmling | — | — | |
| US 50 Bus. | — | — | Pueblo | Avondale | — | — | |
| US 50 Bus. | — | — | — | — | — | — | Serves Olathe |
| US 85 Byp. | — | — | Fountain | Colorado Springs | — | — | |
| US 85 Bus. | — | — | — | — | — | — | Serves Brighton |
| US 85 Bus. | — | — | — | — | — | — | Serves Fort Lupton |
| US 85 Bus. | — | — | — | — | — | — | Serves Platteville |
| US 85 Bus. | — | — | — | — | — | — | Serves Greeley |
| Temp. US 87 | — | — | — | — | — | — | Served Denver |
| US 160 Bus. | — | — | — | — | — | — | Serves Mancos |
| US 160 Bus. | — | — | — | — | — | — | Serves Durango |
| US 160 Bus. | — | — | — | — | — | — | Serves Bayfield |
| US 350 Byp. | — | — | — | — | — | — | Serves Trinidad |
| US 550 Bus. | — | — | — | — | — | — | Serves Durango |
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