The County of Aragon or County of Jaca is a small Frankish marcher county in the central Pyrenean valley of the Aragon river, comprising Ansó, Echo, and Canfranc and centered on the small town of Jaca (Iacca in Latin and Chaca in Aragonese), an area now part of Spain.

It is created by the Carolingians late in the 8th or early in the 9th century, but soon falls into the orbit of the Kingdom of Navarre, into which it is absorbed in 922.

It will later form the core of the 11th century Kingdom of Aragon.