Hasa, Al (äl häˈsä, hăˈsə) [key], region, E Saudi Arabia, on the Persian Gulf. Administrated as the Eastern Province, Hofuf is the chief town. Dates, wheat, and rice are produced. It was taken from the Turks in 1914 by Ibn Saud. The discovery of large oil reserves in the 1930s transformed the region and is Saudi Arabia's chief oil-producing area.