Mosquito Pass is a high mountain pass at an elevation of 13,185 ft (4.019 m),located in the Mosquito Range of central Colorado in the United States. This road has humbled many egos. It’s not for the sissies and shouldn’t be attempted by novice drivers. The road is in dreadful condition and requires strong nerves to negotiate it. It's one of the highest mountain passes of Colorado.
Mosquito pass travels from Colorado Highway 9 north of Fairplay over to the town of Leadville. It is a two way road, although it is tight in some spots and may require careful maneuvering to pass oncoming traffic.It is traversable only on foot or with a proper four-wheel drive vehicle. 2WD vehicles will find it difficult due to the stream crossings and high rocky sections. It'snicknamed the "highway of the frozen death". The pass lies on the boundary between Lake and Park counties between Leadville (west) and Fairplay (east).
Even with a 4WD vehicle, the pass is typically passable only during the summer months. Do not travel this pass in severe weather conditions. Avalanches, heavy snowfalls and landslides can occur anytime, being extremely dangerous due to frequent patches of ice. It has a well-deserved reputation for being dangerous because of unpredictable snowstorms and blizzards, and driving under these conditions, can be extremely challenging. There is a sign on the first part of CO 12 that tells if the pass is open or closed.
The best time to attempt the pass is between late July and early September. With such a high summit altitude the road can be closed anytime due to snowfalls. The zone is prone to heavy mist and can be dangerous in low visibility conditions.
About the origin of the Mosquito pass name, there are lots of versions. One of the most popular says that just after nearby Montgomery was founded, gold was discovered high in the mountains above and gave rise to the town of Mosquito. The name came from a town meeting where a mosquito was crushed between pages of a book during the meeting. It was the only name they could agree on. There is a memorial to Father Dyer at the summit of the pass.
This is not an extreme 4WD pass, but there are parts that need good ground clearance and quite a lot of ascent/decent will be fairly steep. This track can get very muddy and slippery after rain making it challenging to get through. During and after a storm the road may be impassable, even with a four-wheel-drive vehicle. Some road sections may require a high clearance 4WD vehicle, in four-wheel-drive, driven by a driver experienced in 4WD drive techniques to drive the road without getting stuck.
The unpaved sections of the road can be impassable when wet. In any case, driving 4WD is recommended due to uneven surface. You won't be traveling fast - 3 to 8 miles per hour once you head up the pass, and you'll spend a lot of time in low gears. There are no outhouses along this route. Before you head up over the pass, fill up with gas and use the facilities. During and after a storm the road may be impassable, even with a four-wheel-drive vehicle and can easily get muddy if it rains making it challenging to get through.
The pass is two way, so you could start at Fairplay or Leadville. Starting at the intersection of Highways 285 and 9 it heads towards Alma. There is a sign that marks the entrance to 'Mosquito Gulch' - turn left here (Colorado Highway 12). Proper preparation is essential to having a safe, enjoyable trop on this road. Due to the remoteness of the area, take special care to ensure that your vehicle is ready for the trip: inspect all tires and make sure they are properly inflated, check all vehicle fluids, replace worn hoses and belts, empty your RV's holding tank and fill the water tank, purchase groceries and supplies. For the vehicle, bring at least two full-sized spare tires mounted on rims, tire jack and tools for flat tires, emergency flares, extra gasoline, motor oil, and wiper fluid and a radio.
Your wheels will be astounded at the wonderful views of the mountains spread out before you! They are terrible for drivers who are prone to vertigo. In many places the road is bordered by a drop of hundreds of meters (many hundreds of feet) unprotected by guardrails.