While the official western terminus of the road is at the Eastern gate of Yellowstone National Park, some commercially produced maps show US 14 within the park itself starting at a junction with US 89 and US 287 at West Thumb and following the northern shore of Yellowstone Lake.

The road ascends a windy path through steep Shell Canyon and rejoins US 14A at the top of the range at Burgess Junction.

[1] The road is designated as Bighorn Scenic Byway between Shell and Dayton on the eastern side of the mountain range.

From here, it diverges north from I-90 briefly to junction with Wyoming Highway 24 (WYO 24) with access to Devils Tower National Monument.

West of Burgess Junction, US 14A passes through the Bighorn Mountains, reaching a maximum elevation of 9,430 feet (2,870 m).

In the initial 1925 plan, roughly the west half of present US 14A, from Cody to US 310 in Deaver, was assigned the number U.S. Highway 220 (US 220).