DTC - Tunnels 3 & 4
Address: 1865 W. Union Ave Map
City: Sheridan, CO Map
Directions:

Located on Union Ave, just west of Santa Fe.

It is on the North side of Union and you enter the driveway at the Fire Hydrant.  The sign for the entrance is small but just look for the fire hydrant.

Clement #12
Address: 7306 W Bowles Ave Map
City: Littleton, CO Map
Clement #13
Address: 7306 W Bowles Ave Map
City: Littleton, CO Map