As a pass became well-used, it could acquire new characteristics: the trail would become known to many people; it would be given a name; it might become a wagon road, a railroad, or a highway. Use of the mountains changes; new trails or roads are developed that cross previously unused and unnamed areas. Thus, new pass names could be added in the future to this comprehensive listing. Conversely, the use of a pass may decline due to a change in traffic or economic conditions.

A few of Colorado's stunning passes lie in the Maroon Bells-Snowmass Wilderness.

What Is a Pass?

A pass is the point used to cross a ridge that divides two watersheds."Divide" and "saddle" are other descriptive words sometimes used to identify passes. Most passes are the low point between two higher points and are shaped as a saddle; "divide" describes the water division. Some passes are named "gap," yet meet the criteria of a pass as given here.

Passes are usually at a considerable elevation, and most of them are in the high mountain ranges in the western half of the state. Yet watershed divides do occur in the eastern part of the state, and some have enough significance that they have been named.

Many passes bear the name of a stream or some other physical feature located nearby, such as a mountain. Others are named for prominent people in the state's history.

Now, what a pass is not. A pass is not a gap, and a gap is not a pass. A gap is a cut through a rock or mountain barrier that has usually been formed by water. A gap has no watershed division associated with it; rather, the same watershed is present on both sides of the gap.

Some authors consider gaps as passes. Wagon Wheel Gap, in Mineral County, is included in many lists of passes, although there is no change in watershed there. The Rio Grande River runs through the gap and drains both sides toward the east.

The word "gap" is frequently used in the eastern U.S. to name a geographic feature that would be termed a pass in Colorado. Cumberland Gap in the eastern part of Tennessee is a pass by our definition: It is a watershed divide in the Appalachian Mountains.