Area of the Antarctic mainland, coordinates ca. 77°S 30°W. Coats Land lies at the south-east end of the Weddell Sea and is therefore the southernmost coast of the Atlantic Ocean, although its southern shore (and, in fact, most of it) marks the edge of a permanent ice shelf and is not directly approachable by sea. It's also the easternmost reach of the Transantarctic Mountain range.
While there are no clear borders in Antarctica, Coats Land can be roughly defined as bordering Queen Maud Land to the east, the Shackleton Range to the south, the Filchner ice shelf to the south-west and the Weddell Sea to the north-west. It was named by expedition leader William Spiers Bruce after James and Andrew Coats who provided and outfitted the ship for the Scottish National Antarctic Expedition of 1902/4.
It was first sighted by the Scottish expedition in 1903 since no one had managed to reach 74°S in the Weddell Sea since Weddell himself eighty years earlier. It was Shackleton's landing target for his failed transantarctic expedition of 1914. In the end it was the only part of the land they wanted to cross that the crew of the Endurance actually saw. It was further explored by Norwegian Hjalmar Riiser-Larsen in 1930. It hosts one permanent research station, the General Belgrano II operated by Argentina.
Factual sources:
Edinburgh University
PBS: Nova
Adventure Network International
Antarctica Online