Aden (anc. Adane, Attanae, or Arabia Felix), a fortified British seaport town on the S. coast of Arabia and on the gulf of Aden, about 120 m. E. of the entrance to the Red sea at Bab-el-Mandeb, lat. 12° 47' N., lon. 45° 9' E.; pop. about 50,000. It is built on the N. E. end of the peninsula of Aden, and connected with the mainland by a low, sandy isthmus. The latter, united with another peninsula called Jebel Hassan, forms the two extensive harbors of Aden, the best on the Arabian coast. The town stands at the E. base of a volcanic mountain range from 1,000 to 1,800 feet high. It is a place of considerable strength and is well garrisoned, its situation between Asia and Africa resembling that of Gibraltar between Europe and Africa. The superiority of the port and abundant supply of water render Aden a valuable and important station on the way from India to Europe. The inhabitants are Asiatic and African, with a few Europeans, chiefly English. The English political resident is the governing authority. The town is surrounded with gardens and fruit trees. The climate, though dry and hot, is not insalubrious. - In ancient times, Aden was the great centre of trade between Arabia, Egypt, and India. It was destroyed by the Romans in the time of Augustus, but soon revived.

Marco Polo speaks of its wealth and splendor in the middle ages. At the beginning of the 16th century it was so strongly fortified that the Portuguese failed to capture it; but the Turkish domination, from about 1540 to 1030, was injurious; and the imam of Sana and the sultan of Yemen, who successively ruled Aden for the next three generations, completed the work of the Turks, and left the place a heap of ruins in 1705, when it became independent. In 1838 Capt. Haynes proposed to the sultan of Aden to cede the town to Great Britain, and on his declining the English took forcible possession, Jan. 11, 1839. Since that time the town has gained commercial importance. In 1870 the imports from Great Britain amounted to £110,403, and the exports to £2,633.