The county was founded on the Hecho valley (also spelled Echo), which would later become the Kingdom of Aragon. The main characteristic of this valley is the magnificence of its natural environment.

Hecho is a town that stands out for its wonderful popular architecture, and for its remarkable open-air exhibition of contemporary sculpture, but above all, it is beauty of its natural environment that takes most of the credit.

The western valleys of the Aragonese Pyrenees enjoy the effects of the humidity brought by the Atlantic, which forms a magnificent, thick vegetation that houses an immensely diverse fauna.

The Hecho valley follows the course of the Aragon-Subordán river, which narrows at "Boca del Infierno" (the Mouth of Hell), a defile that the river has drilled into the rock. On the valley we also find "Selva de Oza", a thick, gorgeous beech and fir forest.