Hadhramaut or Ḩaḑramawt, coastal district forming a large part of the southeastern Republic of Yemen, extending along the Gulf of Aden to Oman on the east. In addition to the coastal plain, about 48 km (about 30 mi) wide, Hadhramaut contains an interior plateau. Although barren for the most part, the area has a number of valleys that yield luxuriant vegetation. Al Mukallā is the largest town in Hadhramaut. Archaeological researches disclose that Hadhramaut, called Hazarmaveth in the Bible, was the site of a highly developed ancient civilization. Between 1934 and 1967, Hadhramaut formed successively part of the Aden Protectorates and the Federation of South Arabia, under the control of Britain. Area, about 155,400 sq km (about 60,000 sq mi); population 718,008 (1994).