The Ezka river (in Spanish: Esca) is a tributary of the Aragon river that flows along 51 kilometers, mainly through the region of Navarra and to a lesser extent (14 kilometers) through Aragon (province of Zaragoza).

It rises at the junction of the Belagua and Uztárroz rivers in the Navarre town of Isaba (Roncal Valley) and flows south through the valley to its mouth at the Yesa Reservoir, downstream from the Aragonese town of Sigüés (La Jacetania).

[1][2] In times of great pluviometry, overflows of its waters take place that affect the communication way NA-137 (Burgui-Isaba-France).

[3][4][5][6][clarification needed] The waters of this river are used as a bathing area during the summer in the Navarrese town of Burgui and in the Aragonese town of Salvatierra de Esca.

[7][8] Through the waters of this river, the Day of the Almadía takes place, a festival declared a Festival of Regional Tourist Interest in Navarra and a Festival of National Tourist Interest organized by the Cultural Association of Almadieros Navarros, which is held every year in the Navarrese town of Burgui (Roncal Valley).