West of Aspen, the Government Trail (#1980) is one of the most popular trails in the Aspen / Snowmass area. The Government Trail (aka Brush Creek Trail) is a 10 mile route with about 1,100 feet of vertical that is typically ridden one-way from Snowmass east towards Aspen. The trail rolls up and down a couple hundred feet roughly following a contour-line above the valley while passing through aspen and lodgepole pine forests.
To reach the Aspen trailhead from downtown Aspen, head west on SR82 to the roundabout. Turn right on Maroon Creek Road for 1 mile and park at the Recreation Center. The trail starts behind the baseball fields. Use the pedestrian bridge and follow the signs to the Government Trail.
To reach the Snowmass trailhead from downtown Aspen, head west on SR82 for 6 miles. Turn left on Brush Creek Road for 4.5 miles to the Snowmass Village Mall base area where parking is available and there is a bus station which connects with Aspen.
From the Snowmass Village Mall base area, head back towards Aspen down Brush Creek Road for 0.25 miles. Turn left heading west up paved Divide Road for 0.9 miles (no trailhead parking). At the summit, veer left on signed Ditch Trail along irrigation ditch for 1.2 miles passing a sign for the lower end of the Connector Trail. The unsigned start of the Government Trail is on the left and heads back up sharply (it may be tough to see).
Head east up the switchbacked Government Trail for 0.5 miles through mixed aspen and lodgepole pine forest to the intersection with the Connector Trail. The next four miles are rocky, rooty trail segments between ski runs and access roads. This rolling, winding route can be difficult to follow at times as it crosses the ski runs.
Around mile 4.5, the route leaves Snowmass ski area and the quality of the trail improves greatly as it rolls and climbs the ridges on the way to Buttermilk ski area. Past the ski area, there is one final switchbacked descent to the eastern trailhead.
The locals talk about the trail as the Western Government Trail (the first 4.5 miles) and the Eastern Government Trail (the later 5.3 miles). While the Eastern can be fun, the Western is a real grunt. If available, you could use the Snowmass gondola to head up and just ride the Eastern half heading east. Alternately, you can use two of the Snowmass-built mountain bike routes to bypass a good chunk of the Western section (Connector Trail and Cross Mountain Trail).
Note: This trail is closed from May 15 to June 20 annually for elk calving. Also, the trail is adjacent to private property, so make sure to stay on the trail.
Overall, Government Trail is the 27th most popular mountain bike trail of all 176 mountain biking rides in Colorado.