Ross Ice Shelf is a vast ice shelf, almost entirely afloat, occupying the entire southern part of the Ross Sea embayment and ending seaward in a cliffed ice front about 400 miles long and ranging from 15 to 50 meters high. It was discovered on Jan. 28, 1841, by Capt. James Clark Ross, for whom it is named. Ross mapped the ice front eastward to 160W.