US and Interstate Highways in Colorado

Here on this page, you can quickly view facts about the US and Interstate Highways that have in existed in Colorado over the years. The routes are not listed in sequential order. Instead, it is done by "parent", meaning that two-digit routes are followed by their three-digit derivatives (i.e. 25, 225, 70, 270, 470, etc.).

Colored Table Format

White

Currently Active

Blue

Decommissioned

Orange

Never Built and/or Signed

The following tables let you explore:

In all of the tables, click on a route's shield to be taken to that route's entry in my main route listing section.


US Highways in Colorado

The US Highway System was proposed in 1925-'26, and fully implemented in 1927. In Colorado, there was already a state highway numbering system in place, developed in May 1923. So, when the US Highways where marked in Colorado, they were run concurrently over existing state-numbered highways. In some states, the US Highways completely commandeered the highway, but in Colorado, they were allowed to coexist. This arrangement was in place up until 1968.

One thing you will notice looking at the US Highway table is that the year "1936" appears a lot. 1936 was a year of major upheaval, with the US Highways in Wyoming, Colorado, and the Four Corners region all under going massive change. By the time the dust settled, things were totally different from what they had been.

My thanks go to Robb Haukohl, Robert Droz and George Sammeth for contributing information.

US Route
(Click for more info)

Dates Existed in Colo.

State Hwys Run On

Notes

6

1932-Present

4 UT-Leadville
91 Leadville-Empire
(later 78 Vail Pass)
2 Empire-Denver
81 Denver-Wiggins
2 Wiggins-Sterling
(later 2 Denver-Sterling)
14 Sterling-NE

Extended west to Greeley in 1932 as part of Roosevelt Coast-to-Coast Highway, taking over US 38. Extended rest of the way through Colorado in 1937. Routed over Vail Pass 1941.

24

1936-Present

4 Grand Jct-KS

Extended west from Kansas to Limon over US 40N, 40S Limon to Grand Junction. Truncated at I-70 1976.

34

1939-Present

16 Granby-Wiggins
2 Wiggins-Brush
54 Brush-NE

Most sections in Colorado were previously not a US Highway.

36

1930-Present

66 Deer Ridge Jct.-Lyons
7 Lyons-Boulder
2 Denver-Byers
102 Byers-KS

Extended west to Denver 1930. Up newly free Denver-Boulder Turnpike to Estes Park 1967. Extended Estes Park to Deer Ridge Junction 1978.

38

1927-1932

2 Greeley-Sterling
14 Sterling-NE

In original 1926 plan. Deleted in favor of US 6 in 1932.

138

1927-Present

2 Sterling-NE

In original 1926 plan. Used to touch US 38 at Sterling.

40

1927-Present

2 UT-Denver
8 Denver-KS

In original 1926 plan. No major changes west of Limon. Originally US 40N east of that.

40N

1927-1936

4 Limon-KS

West end Limon. Renumbered as part of US 24 in 1936.

40S

1927-1936

4 Grand Jct.-Limon
8 Limon-KS

West end did not touch US 40. Renumbered as US 24 and US 40 in 1936.

340

Never

Limon-KS via Cheyenne Wells

Originally proposed as part of 1926 system, but rejected in favor of US 40N.

46

Never

Grand Jct.-Limon via Buena Vista

Originally proposed as part of 1926 system, but rejected in favor of US 40S.

50

1927-Present

4 UT-Grand Jct.
6 Grand Jct.-KS

In original 1926 plan. No major changes, except for Pueblo Bypass.

350

1927-Present

12 Trinidad-La Junta

In original 1926 plan. No major changes.

450

1927-1934

10 UT-Walsenburg

In original 1926 plan. Renumbered in favor of extended US 160 in 1934.

550

1927-Present

19 NM-Montrose

In original 1926 plan. South end originally Durango. Extended south to New Mexico in 1935.

650

1928-1935

15 Buena Vista-Salida

Route taken over by extended US 285 in 1935.

160

1932-Present

10 UT-Walsenburg
55 Trinidad-Branson
100 Branson-Springfield
116/118 US287-KS
(later 100 Trinidad-KS)

Extended west from Kansas to Trinidad in 1932. KS-Trinidad formerly not a US Hwy. Took over US 450 Walsenburg-UT (current 666) in 1934. Realigned to Four Corners over US 164 in 1970.

560

Never

NM-Cortez

Originally proposed as part of 1926 system, but rejected in favor of US 666 after US 60 changed to US 66 in final plan.

164

1966-1970

40 UT-Cortez

Renumbered as part of realigned US 160 in 1970. Route was formerly not a US Hwy.

666

1927-2003

106 NM-Cortez

North end originally Cortez. Extended northwest to UT in 1970. Renumbered to US 491 in 2003.

84

1938-Present

17 NM-Pagosa Springs

Originally northward into CO on US 666, end Cortez. Routed to NM-Pagosa Springs route in 1942.

85

1927-Present

1 NM-Denver
2 Denver-Greeley
3 Greeley-WY
(later 3 Denver-WY)

Part of original 1926 plan. No major changes, except for I-25.

185

Never

Denver to WY via Longmont and Virginia Dale

Originally proposed as part of 1926 system, but rejected in favor of US 285.

285

1927-Present

17 NM-Alamosa
(later 163 NM-Antonito)
10 Alamosa-Del Norte
15 Del Norte-Buena Vista
8 Buena Vista- Denver
1 Denver-Ft. Collins
14 Ft. Collins-Ted's Place
123 Ted's Place-WY

Originally ran from Denver to Laramie via Longmont and Fort Collins. Extended south from Denver to NM 1935. Deleted north of Denver in 1936. Used to take SH 17 into NM. Rerouted 1942. Rerouted Salida-Buena Vista (SH 291) 1942. North end used current SH 8/Alameda Ave. to downtown. Realigned to Hampden Ave. expy in 1970. Ended at Havana/Colfax, truncated at I-25 1978.

385

1959-Present

51 Granada-Julesburg
166 US138-NE

North of Granada formerly not a US Hwy.

87

1935-Present

1 NM-WY
(later 185 Castle Rock-WY)

At first run on US 85 NM-WY. Route north of Denver changed to Broomfield-Fort Collins-Wellington-WY in 1936. Rerouted to current I-25 (SH 185) north of Castle Rock in 1954.

Today, nonexistent due to I-25.

187

Never


Would have used SH 13 southward from WY border. Shown on 1938 Texaco map, but nothing else.

287

1935-Present

59 OK-Kit Carson

Took over Old US 285. South end originally Denver. South end moved to Fort Collins in 1936 when US 87 rerouted. Extended southeast to OK 1940.

491

2003-Present


Took over US 666 in 2003 after renumbering campaign launched by NM.

393

Never


Number first proposed by NM-CO-UT in 2003 for renumbering US 666. Rejected by AASHTO in favor of US 491.

400

ca.1992-Present


Congressional High Priority Corridor.

US Route
(Click for more info)

Dates Existed in Colo.

State Hwys Run On

Notes

Colorado Interstate Highways

Interstate Route
(Click for more info)

US Highway Alignment

Date Completed

Notes

25

85-87 NM-Castle Rock
87 Castle Rock-WY

1970 (Trinidad-Walsenburg)

Major artery of Front Range Corridor. CDOT continually playing catch-up to increasing traffic on it.

225


1977 (Parker Rd. to I-25)

Inner east Denver beltway, serves east suburbs.

70

6-50 UT-Grand Junction
6-24 Grand Junction-Minturn
6 Minturn-Empire
6-40 Empire-Denver
40-287 Denver-Limon
24 Limon-KS

1992 (Glenwood Canyon)

Originally planned to have west end in Denver. Extended west during planning in 1950s. Main route over mountains via Eisenhower Tunnel.

270


1970 (Vasquez-I-76)

Serves old Stapleton Airport, industrial areas in Commerce City. Extension to US 36 completed 2003

470


If built, would have been completed late 1980s to early 1990s.

Proposed late 1960s as southwest bypass, also to serve fast-growing suburban area. Removed 1976 due to air quality/land use concerns, funding transferred to other projects. SH 470 built in its place.

76

6 Denver-Wiggins
6-34 Wiggins-Brush
6 Brush-Sterling
138 Sterling-NE

1994 (Barr Lake)

First existed as I-80S. One of two I-76s in the US. One of the main routes for transcontinental travel Chicago-Los Angeles.

80S

Same as I-76

In 1975, was not completed

  • I-70 to I-25
  • Barr Lake
  • East of Wiggins

Renumbered to I-76 in 1975, to conform to AASHTO's guidelines frowning on letter suffix routes.

Links:

Last updated 21 May 2004