Gilpin County

Bobtail Road Bridge   [Map · Street View]
Steel through arch bridge over Bobtail Creek on Bobtail Road in Black Hawk
Open to traffic
Built 1999
Tunnel No. 4   [Map · Street View]
Abandoned tunnel on CO 119 near the junction with US 6
Still intact, but boarded up after the roads were realigned to make this tunnel unnecessary
Built 1939
UP - Moffat Tunnel   [Map · Street View]
Tunnel under Continental Divide west of Denver on Union Pacific RR
Open to railroad traffic, including Amtrak's California Zephyr
Built 1923-1928