CASTEL SARRASIN, a town of France, capital of an arrondissement, in the department of Tarn et Garonne, situated on the Songuine or Azine, near its influx into the Garonne, 12 miles west of Montauban. The walls which formerly surrounded the town have been converted into promenades. It has manufactures of serges and other woollen stuffs, hats, and leather, and some trade in corn grown in the vicinity. The town is said by some investigators to receive its name from the erection of its castle by the Saracens, but according to others the present form of the word is only a corruption of Castel sur Azine. The Parliament of Toulouse took refuge within the town in 1595. Population in 1872, 3064.