This is one component of a database of glacial extent for the American West. The purpose of this project is to collect and distribute data concerning the location of and changes in glacial extent over the historic period. Glaciers are found in the states of Washington, Oregon, California, Montana, Wyoming, and Colorado, and perhaps in Nevada, Utah, and Idaho. We have three motivations for this project. First, glaciers are rapidly shrinking due to climate warming. This is true not only for the American West, but for most other regions of the world. Perhaps glaciers are the clearest expression of climate change. Second, assessment of glacier cover and its change is importance to regional stream flow and global sea level. Understanding the changes will allow us to define past contributions and estimate future effects if the glaciers recede drammatically or disappear altogether. Finally, glaciers are fascinating landforms. Under the right conditions they store information on past climates, and create lasting landforms, such as moraines that can also be used to infer past climates.