New South Greenland, sometimes known as Morrell's Land, was an appearance of land recorded by the American captain Benjamin Morrell of the schooner Wasp in March 1823, during a sealing and exploration voyage in the Weddell Sea area of Antarctica. Morrell provided precise coordinates and a description of a coastline which he claimed to have sailed along for more than 300 miles (500 km). Because the Weddell Sea area was so little visited and hard to navigate due to ice conditions, the alleged land was never properly investigated before its existence was emphatically disproven during Antarctic expeditions in the early 20th century.
At the time of Morrell's voyage, the geography of the then-unnamed Weddell Sea and its surrounding coasts was almost entirely unknown, making the claimed sighting initially plausible. However, obvious errors in Morrell's voyage account and his general reputation as a fabulist created scepticism about the existence of this new land. In June 1912, the German explorer Wilhelm Filchner searched for but found no traces of land after his ship Deutschland became icebound in the Weddell Sea and drifted into the locality of Morrell's observation. A line sounding of the sea bottom revealed more than 5,000 feet (1,500 m) of water, indicating no land in near proximity. Three years later, trapped in the same waters with his ship Endurance, Ernest Shackleton was able by similar means to confirm the land's implausibility.
Various explanations for Morrell's error have been suggested, including intentional deception. However, Morrell describes his find briefly and prosaically, evidently seeking no personal credit or glory from the discovery. In his narrative, he assigns the honour to his fellow sealing captain, Robert Johnson, for finding and naming the land two years earlier. Morrell may have been honestly mistaken, through miscalculation of his ship's position (the reported coastline does roughly match the shape of the nearest real one, but offset by a large distance) or by misremembering detail when writing the account after nine years. Alternatively, he may have made the common error of confusing distant icebergs with land, or been misled by the distorting effects of Antarctic mirage. In 1843, British naval explorer James Clark Ross reported possible land in a position close to Morrell's; this land, too, would eventually be proven not to exist.