Emmons Glacier lies on Mount Rainier’s northeast flank in Washington and, at about 4.3 square miles, has the greatest surface area of any glacier in the contiguous United States. Beginning above 13,800 feet, it flows east and then northeast, joining the Ingraham Glacier near Disappointment Cleaver before Little Tahoma Peak separates them, and it descends to a rocky terminus near 5,100 feet. Named for geologist Samuel Franklin Emmons after an 1870 survey, it shifted from rapid retreat in the 1930s to advance after a 1963 rock fall insulated its lower ice, before retreat resumed by 2003. It is also a major climbing route, with Camp Schurman serving as an important base.