U.S. Highway 6 (US 6) is a part of the United States Numbered Highway System that travels from Bishop, California, to Provincetown, Massachusetts. In the U.S. state of Colorado, US 6 is an east–west highway stretching from Utah to Nebraska. Much of the route overlaps other highways in Colorado, and, as a result, much of US 6 is unsigned.
US 6 is concurrent with Interstate 70 (I-70) for a significant portion of its length from the Utah state line to Denver. When the highway enters the western Denver suburbs, US 6 coincidentally aligns with 6th Avenue in the grid system, where it is known as 6th Avenue Freeway. Once it reaches I-25, US 6 travels north briefly, then follows I-76 for most of its length east of Denver. It is unsigned while it is overlapped.
The highest altitude along US 6 is 11,990 feet (3,650 m) at Loveland Pass, where it crosses the Continental Divide. It continues down the Clear Creek valley until it reaches I-70, where it is briefly overlapped until I-70 leaves the Clear Creek valley. US 6 continues down Clear Creek and into Denver, where it turns into a freeway with six lanes. East of Denver, it continues east while joined with I-76 until it reaches Sterling, where it diverges from the Interstate. The last town in Colorado through which it passes is Holyoke.
Colorado Highways: US 6