Auch (French pronunciation: [ᴐʃ] ⓘ; Gascon: Aush [ˈawʃ]) is a commune in southwestern France.

[4] Auch borders thirteen other communes: Barran, Castillon-Massas, Castin, Duran, Lasséran, Leboulin, Montaut-les-Créneaux, Montégut, Ordan-Larroque, Pavie, Pessan, Preignan and Roquelaure.

[7] Centred on the middle Baïse valley, Armagnac is distributed along an east-west axis between Eauze and Auch.

The upper town is linked to the banks of the Gers by the medieval "pousterles", typical narrow streets with steep inclines, and by the monumental staircase inaugurated in 1863.

The lower town was devastated on several occasions (1897, 1952 for the most significant river overflow) before the course of the Gers was recalibrated following the 1977 floods in Gascony.

Augusta Auscorum was one of the twelve civitates of the province of Novempopulana (Gascony) and became the provincial capital after the 409 destruction of Eauze by the Vandals.