According to About.com, Mount Augustus is the biggest rock in the world. This monolith is located in Western Australia's Golden Outback, 286 miles east of Carnarvon.
Mount Augustus covers an area of 18.5 square miles. It rises about 2,815 feet above the plain that surrounds it and 3,625 feet above sea level. The central ridge of Mount Augustus is nearly 5 miles long.
While Uluru, also known as Ayers Rock, is generally considered to be the world's largest, Mount Augustus is about two and a half times larger than Uluru. However, as About.com notes, Uluru is a rock monolith, but Mount Augustus is a monocline.