GAO, a town of French West Africa, the chief town of a circle, in the colony in the French Sudan, on the left bank of the Niger, 400 m. by river below Timbuktu. Pop. , The present town dates from the French occupation in 190o; of the ancient city there are scanty ruins, the chief being a truncated pyramid, the remains of the tomb (16th century) of Mohammed Askia, the Songhoi conqueror, and those of the great mosque. The city of which the French settlement is the successor was founded by the Songhoi, probably in the 7th or 8th century, and became the capital of their empire. In the 14th century Gao was conquered by the king of Melle, and its great mosque was built (c. 1325) by the Melle sovereign Kunkur Musa on his return from a pilgrimage to Mecca.
In the 15th century the Songhoi regained power and Gao at tained its greatest prosperity in the reign of Askia. It did not enjoy the commercial importance of Jenne nor the intellectual supremacy of Timbuktu, but was the political centre of the west ern Sudan for a long period. On the break up of the Songhoi power the city declined in importance. It became subject in 1590 to the Ruma of Timbuktu, from whom it was wrested in 1770 by the Tuareg, the last named surrendering possession to the French. A Frenchman, D'Isalquier (q.v.) spent some years in Gao in the early 15th century. In modern times it was reached by Mungo Park (18o 5) and by Heinrick Barth (1875). It is now the Niger terminus for trans-Saharan motor traffic. From Gao upwards the Niger is navigable for over i,000 miles.
See F. Dubois "La region de Gao" (L'A f rique f rancaises [1909]).