The Ross Ice Shelf is the largest ice shelf in Antarctica, a floating platform of ice roughly 500,809 square kilometres in area — about the size of France — and several hundred metres thick.
Named after Sir James Clark Ross, who encountered it on 28 January 1841, the shelf was originally known as “The Barrier” because its sheer ice front — more than 600 kilometres long and rising 15 to 50 metres above the water — blocked ships from sailing further south. Ninety per cent of the shelf sits below the surface. It floats in the Ross Sea, covering a large southern portion of that embayment and the entirety of Roosevelt Island. Most of the shelf lies within the Ross Dependency, claimed by New Zealand. Ross charted the ice front eastward to 160° W; the feature was formally named Ross Ice Shelf by the United States Board on Geographic Names in 1953. As the largest such structure on the continent, the Ross Ice Shelf remains central to Antarctic glaciology and exploration history.
