“That's Pine Creek up there. Supposedly it's one of only two ways out of Zion Valley. Of course, without a map, good luck surviving.”— Follows-Chalk
The Pine Creek tunnel is a location in Zion Canyon, found along Utah State Route 9. Should the Courier decide to help the Sorrows to flee Zion valley, this is the tunnel that they use to leave.
It is a tunnel with a large gate covering the entrance, with no way to access the inside.
The Pine Creek tunnel appears only in the Fallout: New Vegas add-on Honest Hearts.