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

Colored Table Format
White	Currently Active
Blue	Decommissioned
Orange	Never Built and/or Signed

The following tables let you explore:

US Highways in Colorado. This table gives you
- Dates the highway existed in Colorado.
- State Highways Run On, which lists what state-numbered highways the US route was run along when it was commissioned.
- General notes.
Interstate Highways in Colorado. This gives you
- What US Highway alignment it took over. All the mainline Interstates in Colorado fall along preexisting US Highway corridors.
- When the Interstate was fully completed in Colorado, and where the last segment was that opened.
- General notes, including what its main purpose is.

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

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.

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.

1939-Present

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

Most sections in Colorado were previously not a US Highway.

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.

1927-1932

2 Greeley-Sterling
14 Sterling-NE

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

1927-Present

2 Sterling-NE

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

1927-Present

2 UT-Denver
8 Denver-KS

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

1927-1936

4 Limon-KS

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

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.

Never

Limon-KS via Cheyenne Wells

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

Never

Grand Jct.-Limon via Buena Vista

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

1927-Present

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

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

1927-Present

12 Trinidad-La Junta

In original 1926 plan. No major changes.

1927-1934

10 UT-Walsenburg

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

1927-Present

19 NM-Montrose

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

1928-1935

15 Buena Vista-Salida

Route taken over by extended US 285 in 1935.

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.

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.

1966-1970

40 UT-Cortez

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

1927-2003

106 NM-Cortez

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

1938-Present

17 NM-Pagosa Springs

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

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.

Never

Denver to WY via Longmont and Virginia Dale

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

1959-Present

51 Granada-Julesburg
166 US138-NE

North of Granada formerly not a US Hwy.

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.

Never

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

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.

2003-Present

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

Never

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

ca.1992-Present

Congressional High Priority Corridor.

US Route
(Click for more info)

Dates Existed in Colo.

State Hwys Run On

Notes

US Route (Click for more info)	Dates Existed in Colo.	State Hwys Run On	Notes
	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.
	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.
	1939-Present	16 Granby-Wiggins 2 Wiggins-Brush 54 Brush-NE	Most sections in Colorado were previously not a US Highway.
	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.
	1927-1932	2 Greeley-Sterling 14 Sterling-NE	In original 1926 plan. Deleted in favor of US 6 in 1932.
	1927-Present	2 Sterling-NE	In original 1926 plan. Used to touch US 38 at Sterling.
	1927-Present	2 UT-Denver 8 Denver-KS	In original 1926 plan. No major changes west of Limon. Originally US 40N east of that.
	1927-1936	4 Limon-KS	West end Limon. Renumbered as part of US 24 in 1936.
	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.
	Never	Limon-KS via Cheyenne Wells	Originally proposed as part of 1926 system, but rejected in favor of US 40N.
	Never	Grand Jct.-Limon via Buena Vista	Originally proposed as part of 1926 system, but rejected in favor of US 40S.
	1927-Present	4 UT-Grand Jct. 6 Grand Jct.-KS	In original 1926 plan. No major changes, except for Pueblo Bypass.
	1927-Present	12 Trinidad-La Junta	In original 1926 plan. No major changes.
	1927-1934	10 UT-Walsenburg	In original 1926 plan. Renumbered in favor of extended US 160 in 1934.
	1927-Present	19 NM-Montrose	In original 1926 plan. South end originally Durango. Extended south to New Mexico in 1935.
	1928-1935	15 Buena Vista-Salida	Route taken over by extended US 285 in 1935.
	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.
	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.
	1966-1970	40 UT-Cortez	Renumbered as part of realigned US 160 in 1970. Route was formerly not a US Hwy.
	1927-2003	106 NM-Cortez	North end originally Cortez. Extended northwest to UT in 1970. Renumbered to US 491 in 2003.
	1938-Present	17 NM-Pagosa Springs	Originally northward into CO on US 666, end Cortez. Routed to NM-Pagosa Springs route in 1942.
	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.
	Never	Denver to WY via Longmont and Virginia Dale	Originally proposed as part of 1926 system, but rejected in favor of US 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.
	1959-Present	51 Granada-Julesburg 166 US138-NE	North of Granada formerly not a US Hwy.
	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.
	Never		Would have used SH 13 southward from WY border. Shown on 1938 Texaco map, but nothing else.
	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.
	2003-Present		Took over US 666 in 2003 after renumbering campaign launched by NM.
	Never		Number first proposed by NM-CO-UT in 2003 for renumbering US 666. Rejected by AASHTO in favor of US 491.
	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

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.

1977 (Parker Rd. to I-25)

Inner east Denver beltway, serves east suburbs.

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.

1970 (Vasquez-I-76)

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

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.

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.

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.

US Highway Alignment	Date Completed	Notes
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.
	1977 (Parker Rd. to I-25)	Inner east Denver beltway, serves east suburbs.
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.
	1970 (Vasquez-I-76)	Serves old Stapleton Airport, industrial areas in Commerce City. Extension to US 36 completed 2003
	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.
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.
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.

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Last updated 21 May 2004