a town of Spain, capital of the district of the same name, in the province of Aragon, 45 miles S.W. of Saragossa, N. Lat. 41. 24., W. Long. 1. 35. It stands on the left bank of the river Jalón, near its confluence with the Jiloca, partly on the plain and partly on a rocky slope, which is covered with remains of ancient Moorish fortifications. It contains about 1000 houses, generally spacious and well-built, several squares, the largest of which is used as the market-place, numerous convents, three hospitals, a fort, a provincial and municipal hall, an episcopal palace, a college, barracks, a theatre, and a bull-arena; there are also two collegiatas, or collegiate churches, both of them handsome edifices, and eleven other parish churches. The principal articles of manufacture are coarse brown paper, leather, and woollen stuffs. The soil of the neighbourhood is fertile and well-cultivated. Pop. 7125.

Calatayud (Job's Castle) is a Moorish city, but stands near the site of the ancient Bilbilis, the birth-place of the poet Martial, and was for the most part built out of its ruins.