ORFA, or OURFA, a pachalik or division of Asiatic Turkey. It is almost entirely formed by the windings of the Euphrates and the river Khabour, and occupies a considerable portion of the most barren part of Mesopotamia. It touches on the north and east the pachalik of Diarbekir, and the dependencies of Malatea; and on the south and west it is separated by the Euphrates from the deserts of Syria. The southern part of this province is, for the most part, flat, sandy, and uncultivated, and inhabited by tribes of wandering Arabs, who pitch their tents on the banks of the rivers and in the vicinity of the springs; but towards the north the country is mountainous and better inhabited. In the early ages of the Roman empire this division of Mesopotamia bore the name of Osroene, and had subsisted for 840 years as an independent kingdom, when it was reduced into the form of a Roman province by the Emperor Caracalla. It was finally swallowed up in the Turkish empire. The principal towns are Orfa, Racca, and Soverick.