Monarch Pass (elevation 11,312 feet (3,448 m)) is a high mountain pass in central Colorado, in the Rocky Mountains of the western United States.

The pass is located on the Continental Divide at the southern end of the Sawatch Range along the border between Gunnison and Chaffee counties, approximately 25 miles (40 km) west of the town of Salida. The pass carries U.S. Highway 50 over the Sawatch Range, providing a route between Tomichi Creek in the upper basin of the Gunnison River on the west and the South Arkansas River, a tributary of the Arkansas River, on the east. The pass can be traversed by all vehicles under most conditions and is generally open year-round; however, 7% grades exist, and the area is prone to heavy winter snowfall, often resulting in temporary closures during severe winter storms. Ramps for runaway trucks are located about halfway down both the eastern and western sides of the pass. Much of the highway over the pass is three-lane.

Ten curves have a 35 MPH advisory speed and one curve has a 30 MPH advisory speed. The East Descent has a 6% grade for 10 miles. The West Descent has a 6% grade for 9 miles.

Down hill from the summit, the maximum safe speed is 15 MPH for trucks with a maximum weight of 80,000 pounds. For trucks with a maximum weight of 50,000 pounds the maximum safe speed is 45 MPH.

The pass is widely considered one of the most scenic in Colorado, offering a panoramic view of the southern end of the Sawatch Range from the summit. During the summer, an aerial tram from the parking lot at the summit carries visitors to the top of Monarch Ridge above the pass (at approximately 12,000 feet (3,700 m) above sea level), allowing a wider view of the surrounding peaks. During the winter, visitors enjoy skiing at Monarch ski area. Monarch Mountain Lodge is located about 5 miles from the summit of the pass.

The current Monarch Pass is the third location on the Continental Divide to carry that name. The Original Monarch Pass is just 1.6 miles (2.6 km) northwest of the present pass. A road traversing this first Monarch Pass was constructed in 1880 and served as an important wagon and stage road connecting the town of South Arkansas City (later Salida) on the east side with booming mining camps and the city of Gunnison on the west side. In 1922, the road was improved and rerouted to better accommodate motor vehicles. The new road crossed the divide 0.6 miles (0.97 km) northwest of the present pass. This second Monarch Pass is what is now known as Old Monarch Pass. It remained an important unpaved crossing of the divide until 1939 when yet another highway realignment was necessary.

During the 1930s, efforts were underway to complete the newly designated U.S. Route 50 across America. In Colorado, one of the more difficult challenges was the routing of the new highway over the Continental Divide. It was clear new road would need to be constructed, but there were three competing options for where to cross the divide. Marshall Pass and Cochetopa Pass, both to the south and at lower elevations, were under consideration as was Monarch Pass, the more direct route between Salida and Gunnison. In September 1938, state engineer Charles Vail decided to utilize the Monarch Pass route, but with significant reconstruction and rerouting to reduce grades, minimize tight curves, and keep the roadbed up on sunny slopes where winter snow would be easier to manage. To achieve these objectives, the road was rerouted over what was then called Agate Pass or Agate-Monarch Pass, which now serves as the third Monarch Pass.

The new U.S. Route 50 over the divide was completed, except for paving, in November 1939, and the new pass was initially designated ‘’Vail Pass’’. Area residents objected to the name, and in December 1939, Governor Ralph Carr officially designated the new pass as ‘’Monarch Pass.’’ Soon thereafter, a newly constructed pass on U.S. Route 6 crossing Colorado farther to the north was named Vail Pass.

Once a large wrecking truck overturned on the icy Monarch Pass highway. At least 100 vehicles were held up by that truck. The patrolmen called for volunteers from among the delayed motorists to lift the overturned truck back onto its wheels. In less than 15 minutes, about 50 people combined their muscle power and opened the Monarch Pass to traffic by putting the truck back on its wheels.

The Federal Aviation Administration installed an automated weather station (AWOS) atop Monarch Pass, broadcasting at 124.175 MHz. It provides pilots of small aircraft access to real-time weather conditions near the summit. Aircraft accidents in the vicinity of Monarch Pass are frequent. The high terrain and frequent storms make this route difficult for light aircraft; the pass is steep and narrow, especially when approached from the east, with a sharp turn required at the summit. Many Colorado pilots therefore advise small aircraft to avoid Monarch in favor of the lower, flatter Marshall Pass just a few miles to the south.

On February 17, 2016 at 7:36 p.m. the weather station recorded a wind gust from the west of 148 mph, the highest official gust recorded to date in the state of Colorado by the National Weather Service (NWS). It broke the previous record of 147 mph from January 25, 1971 recorded by the Center for Atmospheric Research (NCAR). These measurements were confirmed by the Colorado Division of Aeronautics and the NWS office in Pueblo, Colorado.

Porphyry Creek SNOTEL is a weather station near the summit of Monarch Pass.

• 
  Summit of Monarch Pass in early May
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  View of Mt. Aetna north of the pass
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  Fall colors along the pass in late September
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  Panoramic View from the Summit

• Monarch Pass, Colorado
• Current road and ski conditions