CO- Alder Creek Pass (UNP)

CO- Antelope Pass

CO- Argentine Pass

CO- Aztec Divide

CO- Aztec Divide (US Hwy. 160-491)(UNP)

CO- Barker Reservoir Summit

CO- Bassam Park Pass

CO- Bathtub Pass

CO- Battle Mountain Summit

CO- Baxter Pass

CO- Bells Gap

CO- Berthoud Pass

CO- Big Creek Pass (UNP)

CO- Bigelow Divide

CO- Black Bear Pass

CO- Black Mesa Summit

CO- Black Sage Pass

CO- Blowout Pass

CO- Blue Hill

CO- Blue Mesa Summit

CO- Bolam Pass (Forest Rd. 578)

CO- Bolam Pass (True Summit)

CO- Boreas Pass

CO- Boulder Pass

CO- Breakneck Pass

CO- Browns Pass

CO- Buckhorn Pass

CO- Buffalo Pass (Jackson Cnty.)

CO- Buffalo Pass (Routt/Jackson Cnty.'s)

CO- Bunker Hill

CO- Buzzard-Muddy Divide

CO- Buzzard Pass

CO- Calamity Pass

CO- California Pass

CO- Cameron Mountain Pass

CO- Cameron Pass

CO- Campion Pass

CO- Carnero Pass

CO- Carson Pass

CO- Cat Creek Gap

CO- Cement Creek Pass (UNP)

CO- Cerro Summit

CO- Cherry Creek Pass

CO- Chillycoat Pass

CO- Chimney Rock Pass (UNP)

CO- Cinnamon Pass

CO- Clover Creek Pass (UNP)

CO- Coal Bank Pass