Guarda (gwärˈdə) [key], city (1991 pop. 18,215), capital of Guarda dist., N central Portugal, in Beira Alta. On the slopes of the Serra da Estrela, it is Portugal's highest city (c.3,400 ft/1,040 m) and is a winter sports resort. Guarda is also the commercial center of an agricultural region, producing metals, leather, and alcoholic beverages. It has an old fort, a castle, and a Gothic cathedral.