Ubirr, once referred to as Obiri Rock, so-named by C. P. Mountford, is a rock formation within the East Alligator region of Kakadu National Park in the Northern Territory of Australia, and is known for its rock art. It consists of a group of rock outcrops on the edge of the Nadab floodplain where there are several natural shelters that have a collection of Aboriginal rock paintings, some of which are many thousands of years old.