city, eastern San Luis Potosí estado (state), northeastern Mexico. It lies along the Tampaon (or Valles) River, west-southwest of Tampico. Sugarcane, citrus fruits, avocados, coffee, tobacco, and cattle are processed there, and lumbering (principally pine) is also important. The city is a commercial centre and a transportation hub that is easily accessible by highways and by railroad. Pop. (2000) 105,721.