Keystone -	Red Cone / Webster Pass are listed as trail systems in the area of Keystone. Vail and Radical Hill are other trail areas. Radical Hill is listed as being connected with Red Cone.
Northern Crested Butte -	Slate and Gothic Roads are listed as trail systems in the Northern Crested Butte area. There are a few more challenging trail systems known as Gunsight Pass, Schofield Pass and Crystal River.
Eastern Crested Butte -	Pearl Pass, Taylor Pass and Italian Creek Road are listed as three challenging trails that all connect to make a loop, and can be accessed from the city of Aspen. These trails are described as offering spectacular views.
St. Mary's Glacier -	Consists of two trail systems, St. Mary's and Empire. Though St. Mary's is the larger of the two areas, Empire is said to be a fun place to ride because it doesn't take very long to get above the tree line.
Alpine Loop -	Alpine Loop is said to be perhaps the best known area for trails in Colorado. Cinnamon Pass and Engineer Pass are the two main trail areas. California Gulch is another.
Texas Creek -	The area of Texas Creek is located along the Arkansas River in the high mountain desert of Central Colorado. In the summertime, temperatures are said to be higher here than most other places in Colorado. At higher than 9,000 feet in elevation, adequate jetting is required.
Vail -	This trail system near Vail is said to be heavily forested and includes numerous logging roads that have good views of nearby ski resorts and other mountains.
Taylor Park -	Described as Colorado's premier dirt bike / atv area, Taylor Park is said to have a large number of trails offering days and days of riding. One source lists Taylor Park as having hundreds of miles of ATV trails and Jeep roads and many single track trails for dirt bikes. Taylor Park is located in southwest Colorado.