The river Jalón (Latin: Salo) is located in the northeast of Spain, and is one of the principal tributaries of the Ebro. It has a length of 224 kilometres (139 mi) and drains a basin of 9,338 square kilometres (3,605 sq mi). The flow rate in Calatayud is 20.8 cubic metres per second (730 cu ft/s), but is highly irregular due to the great range of Mediterranean rainfall patterns.
Path of the Jalón river 
|⁃ location||Medinaceli, Iberian System, Castile and León|
|⁃ elevation||1,192 m (3,911 ft)|
|Torres de Berrellén, Zaragoza, Aragón|
|209 m (686 ft)|
|Length||224 km (139 mi)|
|Basin size||9,338 km2 (3,605 sq mi)|
|⁃ average||20.8 m3/s (730 cu ft/s)|
|⁃ left||Nágima, Henar, Manubles, Isuela|
|⁃ right||Piedra, Jiloca|
The course of the river forms the main communication route between the Castilian Plateau and the Ebro. Until the late twentieth century, roads and railways between Madrid and Zaragoza followed this path.
The Jalón rises in one of the springs at the foot of the Sierra Ministra, called Fuente Vieja (Old Fountain) located at the base of Monteagudillo, a hill in Benamira, Medinaceli (Soria), and then runs through Arcos de Jalón, to Monreal de Ariza, province of Zaragoza, Aragón.
The tributary river Nágima joins at Monreal de Ariza and the Henar at Cetina before the river enters a limestone gorge at Alhama de Aragón. The Jalón then meanders through the Paleozoic zones of the Cordillera Ibérica near Bubierca, being joined by the Piedra and the Manubles at Ateca. At Calatayud, the river expands into a broad valley and is joined by the Jiloca, Perejiles and Ribota. The next section meanders through the Sierra de Algairén and the Sierra de la Virgen.
Much of the course of the Jalón has been declared a Special Zone for Bird Protection. Birdlife includes falcons, eagles, and vultures. Other species include owls, wrens, and herons. Poplar, willow and ash. Carp, trout and eels were economically important in the past and are returning as pollution is being combated. The Plan Hidrológico del río Jalón, a river management plan, was adopted by the Spanish Ministry of the Environment and the governments of Aragon, Castile and León and Castile-La Mancha in 2007.
- "The Coombs of the River Jalon". CAI Tourism of Aragon. Retrieved 2009-11-20.[permanent dead link]
- "Jalón". CAI Tourism of Aragon. Retrieved 2009-11-20.
- "Variables Ambientales". Confederación Hidrográfica del Ebro. Archived from the original (Spanish) on 2009-12-01. Retrieved 2009-11-23.
- "Plan Hidrológico del río Jalón" (Spanish). Ministerio de Medio Ambiente. 2007. Retrieved 2009-11-23.
- Cf. p. 541, "La Hidronimia de Galicia: tres estratos ..". http://www.mondonedoferrol.org/estudios-mindonienses/MINDONIENSES%2024%20[protegido].pdf