U.S. Route 36 (US 36) is a United States highway that travels from Rocky Mountain National Park, Colorado to Uhrichsville, Ohio.

At its west end, the road connects several small mountain towns such as Estes Park and Lyons to the larger metropolitan areas of Boulder and Denver.

As it continues eastward, it connects to several other small towns and rural highways on the plains before crossing the state line into Kansas.

Just outside Lyons, US 36 turns south at a signalized intersection onto two-lane North Foothills Highway, while SH 66 continues east to Longmont.

One block farther south, SH 7 diverges from its overlap with US 36 by turning east onto Arapahoe Avenue.

Northwestbound traffic approaching Boulder on the turnpike can stop at the Davidson Mesa Overlook, a scenic overlook providing a panoramic view of the Front Range mountains, the City of Boulder, and its famous Flatirons rock formation; a monument to the Denver-Boulder Turnpike's original builders is also located here.

[4] Continuing southeast, the road enters the fast-growing Denver suburbs of Broomfield and Westminster, which have become popular locations for High-Tech businesses, which can be seen lining the turnpike.

The US 36 bikeway, part of the multi-modal Fastracks US 36 Express Lanes Project, mostly parallels the road between Table Mesa Drive in Boulder and 80th Avenue in Westminster, the first 11-mile stretch between Westminster and Louisville/Superior opening on Bike-to-Work Day in June 2015,[5] the full route to Table Mesa in Boulder in March 2016.

Many of the towns on this desolate 105-mile (169 km) section of highway are so small that they do not provide basic traveler services such as gasoline, and signs caution winter drivers that there is no snowplowing at night.

Phase 2 of the project, anticipated to be complete by early 2016, will extend the HOT lanes from 88th Street to Table Mesa Drive in Boulder, Colorado, through a public–private partnership.

[14][15] The west end of State Highway 102 was initially at Strasburg,[16] but by 1924 it had been shifted to Byers, using the present County Roads 10 and 197 to return to current US 36.

Paving began in 1937–1939 and was completed in 1947–1949, including a realignment off County Roads DD and 12 north of Idalia.

[15] In 2012, the turnpike was also given the honorary name Buffalo Highway in recognition of the University of Colorado's mascot,[18] though this name has not achieved common use.

Returning to Colfax Avenue east of Denver, the first part of I-70 in that area opened in 1961–1962, bypassing Watkins and Bennett and carrying US 36 (and US 40/US 287).

[15] In early September 2013, a 31-mile (50 km) section of US 36 from Estes Park to Boulder was closed due to damage from the 2013 Colorado floods.

[21] In July 2019, cracks appeared on the eastbound lanes of the highway in Westminster due to shifting soil underneath.