CLIFTON, a town of Arizona, U.S.A., on the San Francisco river and the Southern Pacific railway, near the eastern boundary of the State; the county seat of Greenlee county. The population in 193o was 2,305. It is in the Morenci-Metcalf copper-mining district, which through 1925 had produced 1,6S7,518,000 lb. of copper. The smelter at Clifton in 1925 treated 179,717 tons of concentrates, yielding J9,272,857 lb. of copper. Clifton was set tled about 187o, and was incorporated in 1908. It is the oldest copper-mining camp in the State.