U.S. Route 40 (US 40) is a part of the U.S. Highway System that travels from Silver Summit, Utah, to Atlantic City, New Jersey.

The route continues a generally easterly course though Moffat and Routt counties, passing through several small communities along the way.

Among the sights to be seen along US 40 is Lake Steam Bath, once the location of a thriving health industry centered on tuberculosis sanatoriums.

From there, it leaves US 287 and continues east through the towns of Cheyenne Wells and Arapahoe before entering the state of Kansas.

It heads southeast to leave Byers and travel along the flat plains of eastern Colorado for the next several miles.

The highway passes through the tiny community of Lowland, where it has another interchange with I-70/US 40/US 287 (exit 336), before crossing a creek to enter the small town of Agate along 1st Avenue, with SH 40 coming to an end shortly thereafter at a junction with Main Street.

The entire length of SH 40 is a rural, two-lane, state highway, running parallel to both the eastbound lanes of modern I-70 to its north, as well as a railroad track to its south.