Aragón River through the Jacetania Nature · Jaca, La Jacetania, Huesca Image of Jaca, not of the place itself. The Aragón river rises in the glacial cirque of the Astún valley, in the municipal district of Jaca (La Jacetania, Huesca), at about 2,050 metres of altitude, fed by the Escalar and Truchas glacial lakes (ibones). From its source it flows from north to south through the Aragón or Canfranc valley until it reaches Jaca, where its course turns west towards Navarre. The Collarada, the highest peak in the area at 2,886 metres, dominates the basin, and heavy snowfall causes major floods in spring, added to those of autumn. The strongly oceanic character of the climate favours the beech and fir forests typical of the high Pyrenean valleys. Photo: Jl FilpoC (CC BY-SA 4.0) What to see and do in Jaca