GUAYMAS or SAN JOSE DE GUAYMAS, a seaport of Mexico, in the State of Sonora, on a small land-locked bay opening into the Gulf of California a few miles west of the mouth of the Yaqui river, in lat. 27° 58' N., long. I I o° 58' W. Pop. (1930) The harbour is one of the best on the west coast of Mexico, and the port is a principal outlet for the products of the large State of Sonora. The town stands on a small, arid plain, nearly shut in by mountains, and has a very hot, dry climate. It is connected with the railways of the U.S. by a branch of the Southern Pacific of Mexico from Nogales, Sonora, and is 265m. S. by W. of the frontier town of Nogales, where that line enters Mexico. The exports include gold, silver, hides and pearls.