CALAHORRA, the capital of the judicial district and diocese of the same name, in the province of Logroño, Spain, 24 miles S.E. of Logroño, in 42° 12'N. lat., 2° 0' W. long. It occupies an elevated site on the left bank of the River Cidacos, near its junction with the Ebro, and contains a cathedral in the mixed Gothic style, dating mainly from the 15th century, an episcopal palace, and several conventual and other schools. The climate is cold and damp, but the soil in the neighbourhood produces in abundance grain, pulse, flax, wine, and oil. Population in 1860, 7106. Calahorra is the ancient Calagurris Nassiea, celebrated for its extraordinary fidelity to Sertorius in his war with Pompey and Metellus; and in the suburbs may still be traced the remains of an ancient Roman circus, an aqueduct, and a naumachia. Under the empire it was a municipium, and enjoyed the rights of Roman citizenship. It was the birthplace of Quintilian.