SH 318's western terminus is at Brown's Park Road at the Utah state line, and the eastern terminus is at U.S. Route 40 (US 40) in Maybell.

SH 318 runs 60.7 miles (97.7 km), starting north of the Green River in an isolated area known as Browns Park.

It connects at the Utah state line with gravel surfaced Brown's Park Road.

The highway runs southeast, passing Browns Park National Wildlife Refuge and continuing southeast when the Green River turns south into Dinosaur National Monument.

Media related to Colorado State Highway 318 at Wikimedia Commons