EBRO (anc. Iberus or Hiberus), the only one of the five great rivers of the Iberian Peninsula which flows into the Medi terranean. The Ebro, approximately 465 m. in length, rises at Fuen tibre, a hamlet among the Cantabrian mountains, in the province of Santander; at Reinosa, 4 m. E., it is joined on the right by the Hijar, and thus gains considerably in volume. I't flows generally east by south through a tortuous valley as far as Miranda de Ebro. The chief cities on its banks are Logrono, Calahorra, Tudela, Saragossa and Caspe. Near Mora in Catalonia it forces a way through the coastal mountains, and, passing Tortosa, falls into the Mediterranean about 8o m. S.W. of Barcelona. It drains an area of nearly 32,00o sq.m. Its principal tributaries are—(right) the Jalon with its affluent the Jiloca, the Huerva, Aguas, Martin, Guadalope and Matarrana; (left) the Ega, Aragon, Arba, Gallego and the Segre with its system of confluent rivers. The Ebro and its tributaries have been utilized for irrigation since the Moorish conquest; the main stream becomes navigable by small boats about Tudela; but seafaring vessels cannot proceed farther than Tortosa. The great Imperial Canal, begun under the emperor Charles V., proceeds along the right bank from a point about 3 m. below Tudela, to El Burgo de Ebro, 5 m. below Saragossa; the irrigation canal of Tauste skirts the opposite bank for a shorter distance; and the San Carlos or New Canal affords direct com munication between Amposta at the head of the delta and the harbour of Los Alfaques.