Mount Blue Sky Scenic Byway

Idaho Springs to Evergreen

Front Range · Colorado · United States

Key measurements

Distance

60.6 miles

Elevation gain

7,460 ft

Elevation loss

7,234 ft

High point

14,128 ft

Low point

7,556 ft

Net change

223 ft (7,570 ft to 7,793 ft)

Surface

Paved

Route type

point-to-point

Route Overview

This route climbs from the historic gold-mining valley of Idaho Springs at 7,555 feet up into the high alpine peaks of Colorado's Front Range, reaching a summit altitude of 14,128 feet before descending into the montane forests of Evergreen.

The centerpiece of the 60.5-mile journey is the out-and-back spur along Highway 5 up Mount Blue Sky—the highest paved road in North America. Riders encounter more than 7,400 feet of total vertical gain through sharply contrasting ecosystems, moving rapidly from narrow canyon floors up through dense lodgepole pine, past subalpine lakes, and across miles of exposed alpine tundra above timberline.

Key Segments & Geographic Transitions

Chicago Creek Canyon Climb — Miles 0.1–13.2

Leaving the Clear Creek valley floor at Idaho Springs, CO-103 heads south, tracking the narrow bed of Chicago Creek. The road climbs steadily through a tight canyon shaded by lodgepole pine, Douglas fir, and aspen groves. The pavement winds through gentle canyon curves before steepening as it rises toward Echo Lake, climbing nearly 3,000 vertical feet to reach the junction with CO-5 at 10,600 feet.

Mount Blue Sky Summit Highway — Miles 13.3–42.0

Turning onto CO-5 at Echo Lake initiates the out-and-back ascent to Mount Blue Sky. The road quickly breaches timberline around 11,500 feet, leaving forest behind for expansive tundra, sheer granite faces, and massive glacial cirques. Switchbacks step up past Summit Lake before making the final push to 14,128 feet near the summit. Guardrails are non-existent above tree line, and the road surface features frost heaves, buckles, and severe melt-thaw weathering. After reaching the turn-around point, the segment backtracks down the same ribbon of asphalt to rejoin CO-103 at Echo Lake.

Echo Lake to Squaw Mountain Crest — Miles 42.0–52.0

Rejoining CO-103 heading east from Echo Lake, the route contours along high ridges through subalpine forest within the Arapaho National Forest. The road carries wide, sweeping curves as it traverses high-elevation terrain around Squaw Mountain, offering periodic glimpses south toward the Mount Evans Wilderness and east toward the Denver basin.

Squaw Pass Descent — Miles 52.1–58.7

Continuing east on Route 103, the road begins its sustained descent off the Squaw Pass ridge line. The ecosystem transitions gradually from high-altitude spruce and fir down into montane ponderosa pine and mountain meadows. The road features consistent, flowing curves as it loses elevation heading toward Jefferson County.

Evergreen Foothills Approach — Miles 58.7–60.5

The final short segment onto Route 66 transitions into the residential foothill canyons surrounding Evergreen. The road descends through gentle terrain bordered by ponderosa pine, finishing at Ellingwood Trail near Evergreen's western edge.

Seasonal & Environmental Context

This route crosses extreme elevation zones, making season and weather timing critical. Highway 5 (Mount Blue Sky) is seasonal, generally open only from late May through early October, depending on snow accumulation.

At 14,000 feet, weather conditions bear little resemblance to those at the base. High winds, freezing temperatures, and sudden snowfall can occur near the summit even in mid-summer. Afternoon thunderstorms develop rapidly over the peaks during summer months, bringing dangerous lightning, hail, and heavy rain to exposed stretches above timberline. Temperatures at the summit are routinely 30°F to 40°F colder than in Idaho Springs or Evergreen.

Logistics & Services

Fuel and full services are available at the origin in Idaho Springs and at the terminus in Evergreen. There are no gas stations along CO-103 or CO-5.

The US Forest Service requires a timed-entry reservation permit to drive CO-5 up Mount Blue Sky during peak operational months; check access requirements in advance. Cellular coverage is unreliable or absent above Echo Lake and across much of the high mountain ridge.

Important Considerations

Rapid elevation change from 7,500 feet to over 14,128 feet can induce altitude sickness, lightheadedness, or shortness of breath. Staying hydrated is essential.

The pavement on CO-5 is rough, uneven, and heavily impacted by winter frost heaves, with deep dips and asphalt cracks near the summit. The road lacks guardrails along steep cliff edges. Mountain goats and bighorn sheep frequently sit on or cross the roadway near Summit Lake and the upper switchbacks.

Timed Entry & Seasonal Access: Vehicle and motorcycle access to Mount Blue Sky requires a timed-entry reservation during the operating season. The summit road is seasonal and typically operates from around Memorial Day through Labor Day, weather permitting. Check current Recreation.gov and Colorado road conditions before travel, as closures can occur because of weather, events, or road conditions.