Red Hill Pass

Red Hill Pass carries US-285 across the northern end of South Park, in the foothills of the Mosquito Range in Park County, Colorado. It sits about 6 miles northeast of Fairplay, the county seat. The summit is the highest point on US-285. Exact elevation is a little fuzzy: USGS-cited sources put it at about 9,993 ft, while the route description for US-285 lists 10,051 ft and an NWS forecast point at the pass reads 10,013 ft. Call it right around 10,000 ft and do not trust any single hard number.

For all that altitude, this is a broad, mild crossing, not a white-knuckle grade. Wikipedia, citing USGS topographic mapping, says the pass is easily traversable by most vehicles and rarely closes in winter. The commonly cited grade is about 6%, but that figure comes from road-enthusiast sites (mesalek.com, dangerousroads.org), not a CDOT survey, so treat it as ballpark. If you are hauling north on US-285 from the New Mexico line toward Denver, Red Hill is a high point you pass over on the way to Jefferson, Kenosha Pass, Bailey, and Conifer, not a major climb you fight.

The real worry here is weather, not slope. South Park is open, high, and exposed, and wind plus snow can build whiteouts and ground blizzards that shut the road. One important note for drivers: the dangerous truck reputation people attach to US-285 belongs to Crow Hill at Bailey, a separate spot roughly 50 miles east and about 3,000 ft lower. Do not confuse the two. Red Hill Pass itself is the calm one.

• Highest point on US-285; summit elevation is about 9,993 ft per USGS-cited sources, with other references at 10,013 ft and 10,051 ft (Wikipedia / NWS Denver-Boulder)
• Located in the Mosquito Range foothills at the north end of South Park, about 6 mi northeast of Fairplay, Park County (USGS / Wikipedia)
• Commonly cited grade of about 6%, from road-enthusiast sites rather than a CDOT survey (mesalek.com / dangerousroads.org)
• Broad, mild pass that is easily traversable by most vehicles and rarely closes in winter (Wikipedia, citing USGS topo)
• US-285 is a chain-law and Must-Carry corridor; CMVs over 16,000 lb must carry chains Sept 1 to May 31 (CDOT)
• Noncompliance fine is about $500 plus a $79 surcharge; getting stuck and blocking the road runs $1,000 plus a $157 surcharge (CSP / CDOT)
• No runaway truck ramp on US-285 anywhere; Colorado's 13 ramps sit on I-70, US-550, US-50, US-160, US-141 and US-40 (Colorado Sun, 2023)

US-285 is a designated chain-law corridor under Colorado's Must-Carry Law. From September 1 through May 31, commercial vehicles over 16,000 lb combined weight (or built for 16 or more passengers) must carry chains or approved traction devices the whole season, even when no chain law is posted. When conditions get bad, the Colorado State Patrol and CDOT post levels. Code 17 means single-drive-axle combination trucks must chain or run approved traction devices, and other CMVs need chains, traction devices, or snow tires, which keeps the road open short of a full shutdown. Code 18 means every commercial vehicle has to chain up. Red Hill Pass has no fixed seasonal closure and stays open year-round; it rarely closes. When it does close, that is wind and blowing snow on the exposed South Park crossing, decided in real time and posted on COtrip.org and CDOT signs, not on any calendar. One verified example: US-285 shut down between Fairplay and Grant on January 5, 2015, when NWS warned of gusts up to 80 mph.

US-285 was commissioned along its present Denver-to-New Mexico run in 1936, mostly replacing older state-numbered highways and absorbing the short-lived US-650 that had existed from 1926. Through South Park, the modern truck route traces a 19th-century corridor: between Bailey and Como, US-285 largely follows the old Denver, South Park and Pacific Railroad, a narrow-gauge line that served the mining country. The pass takes its name from the red-colored hills around the summit, most visible on the south side, not from any event (Wikipedia, citing USGS).

The region's settlement runs older than the highway. Fairplay, just southwest of the pass, was founded in 1859 during the Pikes Peak Gold Rush and became the Park County seat in 1867. The 9,993 ft elevation figure comes from USGS mapping, specifically Glenn Scott's "Historic Trail Map of the Denver 1 by 2 Degree Quadrangle," published by USGS in 1999.