From Kawuneeche Visitor Center at the park's Grand Lake Entrance, Trail Ridge Road follows the North Fork of the Colorado River north through the Kawuneeche Valley. There are several trailheads along this section of the road, notably the Colorado River Trailhead, which is the western terminus of the road segment closed during the winter.
The road crosses the Continental Divide at Milner Pass (elev. 10,758 ft or 3,279 m) and reaches a maximum elevation of 12,183 ft (3,713 m), near Fall River Pass (elev. 11,796 ft or 3,595 m). Near the highest point on the road is another pass, Iceberg Pass (elev. 11,827 ft or 3,605 m).
According to construction contracts and park maintenance files, the east end of the road is located at the Fall River entrance, however some guides list Deer Ridge Junction as the east end.[5]
Trail Ridge is a high, flat spur range extending east from the main range of the Rockies between Fall River in the North and the Big Thompson River in the South. The road follows Trail Ridge from the Fall River Pass near Alpine Visitor Center to the Deer Ridge Junction.[5]
Climate
Climate data for Trail Ridge High Point 40.4093 N, 105.7142 W, Elevation: 12,149 ft (3,703 m) (1991–2020 normals)
Trail Ridge had been used by Native Americans to cross the mountains between their home lands in the west and hunting areas on the east side. Arapahoe Indians called the trail located on the ridge as "taienbaa" ("Where the Children Walked") because it was so steep that children could not be carried, but had to walk. The Ute tribe crossing the mountains at Forest Canyon Pass marked their route with stone cairns. The present park Ute Trail follows partially that ancient route.[5]
On the west side, about 1880, a wagon road was constructed along the Kawuneeche Valley from the town of Grand Lake to the mining camps of Lulu City and Gaskill. The camps were abandoned after a few years when short-lived mining boom ended and later the road was used only occasionally by hunters and tourists.[5]
Fall River Road was the first road into the park's high country. It opened in 1921 and quickly proved inadequate for motor travel as a single-track road with steep grades (up to 16%), tight curves and a short annual season due to snowpack.[7] Construction began in 1929 and was complete to Fall River Pass by July 1932, with a maximum grade of 7%. The road was complete through the Kawuneeche Valley to Grand Lake in 1938.[8] The route followed what was known to local Arapaho Indians as the Dog Trail. Internal opposition to the construction of a road through the park's alpine tundra was overruled by National Park Service director Horace Albright, who wished to encourage park visitation. The road was designed to intrude as little as possible into the landscape, in accordance with Park Service design principles.[9]
^"Forest Health". National Park Service. Retrieved January 12, 2013. Road crews use tall and narrow trees as snow poles to mark road edges affected by deep snow. These snow poles help facilitate plowing operations throughout the year, especially when opening Trail Ridge Road.
^"PRISM Climate Group, Oregon State University". PRISM Climate Group, Oregon State University. Retrieved October 10, 2023. To find the table data on the PRISM website, start by clicking Coordinates (under Location); copy Latitude and Longitude figures from top of table; click Zoom to location; click Precipitation, Minimum temp, Mean temp, Maximum temp; click 30-year normals, 1991-2020; click 800m; click Retrieve Time Series button.
^"Scenic Drives". Rocky Mountain National Park. National Park Service. Retrieved August 23, 2007.