According to the U.S. Forest Service, Shoshone National Forest has the greatest number of glaciers of any National Forest in the Rocky Mountains. The forest recreation guide lists 16 named and 140 unnamed glaciers within the forest, all in the Wind River Range. Forty-four of these glaciers are in the Fitzpatrick Wilderness, centered around the highest mountain peaks. However, the state water board for Wyoming lists only 63 glaciers for the entire Wind River Range, which includes glaciers in adjacent Bridger-Teton National Forest. Researchers claim that for most of the period that glaciers have been known to exist in the forest, that they have been in a state of general retreat, with glacial mass losses of as much as 25 percent between the years 1985 and 2009.