Gistaín is a municipality in the province of Huesca, in the autonomous community of Aragon, Spain. It is located in the mountainous terrain of the Aragonese Pyrenees, in the comarca of Sobrarbe.
According to the 2004 census carried out by the Instituto Nacional de Estadística (INE), the municipality had a population of 161 inhabitants. This small population figure reflects the character of Gistaín as a sparsely populated rural municipality typical of the Pyrenean valleys of northern Huesca.
The village sits in the Chistau valley, alongside the Cinqueta river, and its traditional stone architecture and mountain setting are characteristic of the area.