(formerly Santo Tomé de Guayana), a city in eastern Venezuela, in Bolívar State. Port on the right bank of the Orinoco River, at the Orinoco’s confluence with the Caroní River. Created in 1961 by merging the settlements of Puerto Ordaz, San Felix, Matanzas, Caruachi, and Castillito. Population, 127,700 (1969).
A railroad branch line links Ciudad Guayana with Cerro Bolívar, where there are iron-ore deposits. The city is the center of Venezuelan Guiana, a large, developing region. The first stage of a metallurgical complex has been completed. There are also enterprises of the pulp-and-paper, nonferrous metal, and chemical industries. In the surrounding region, iron and manganese ores are mined and crude oil is extracted.