Eastern part of the Filchner-Ronne Ice Shelf, the second of Antarctica's huge ice shelves, at the south end of the Weddell Sea. Roughly located south of 77°S and between 30°W and 40°W, defined by Coats Land to the east and south, the open (well, iceberg-laden) waters of the Weddell Sea to the north, and Berkner Island to the west. It occupies about 100.000 km².
It owes its name to Wilhelm Filchner, the Swiss-German explorer who first set foot on it in 1912 during the Deutschland expedition. Originally named Kaiser Wilhelm after the German emperor, the Kaiser himself decreed that it be named after its discoverer.
The Filchner ice shelf is the deepest of the major ice shelves and drains a fairly big sector of east Antarctica. The fact that its edge is far south, it's relatively narrow and that it's constantly fed by large inland glaciers (Recovery Glacier flowing in from the south-east contributes about half its ice volume) allows it to maintain a depth of around 600m until very near its edge. It discharges about 75km³ of ice yearly, much of that during major calving events that occur every 50 years or so. The last such calving occurred in 1986 resulting in an iceberg with a surface area of about 11.500km² and increased the alarm concerning the rapid disintegration of the west Antarctic ice mass.
Factual sources:
Canadian Remote Sensing Society
New York University
Southampton Oceanography Centre