East of the coast of El Hasa, in the Persian Gulf, a little to the south of the port of El Katif, which, if rightly identified with the ancient Gerrha, has been celebrated throughout history as the mart of Indian trade, the starting-point of caravans across Arabia.
In the territory controlled by the Emir of Nejd the official religion is Wahabi, but a few Shiahs are still to be found in the districts of El Hasa and Hofuf.
The XXXII.-3 Euphrates and Tigris have within historical times silted up their mouths to an extent that has materially altered the coast-line of the Gulf and these rivers seem destined in the future to unite El Hasa to Fao, just as in the past they produced the fertile plains of Mesopotamia.
Up to 1913 the Turks exercised the right of suzerainty over the maritime districts of El Hasa and Hofuf, and claimed it in Qatar and Kuwait.
Oman and Hasa between them occupy the eastern coast districts of Arabia to the head of the Persian Gulf.