 Mules are still used extensively to transport cargo in rugged roadless regions, such as the large wilderness areas of California's Sierra Nevada mountains or the Pasayten Wilderness of northern Washington state.Commercial pack mules are used recreationally, such as to supply mountaineering base camps, and also to supply trail building and maintenance crews, and backcountry footbridge building crews.As of July 2014, there are at least sixteen commercial mule pack stations in business in the Sierra Nevada.