Ustou
Commune
Ruins of the chateau of Mirabat
Location of Ustou
Ustou Show map of France Ustou Show map of Occitanie
Coordinates: 42°47′59″N 1°15′52″E / 42.7997°N 1.2644°E / 42.7997; 1.2644
Country	France
Region	Occitania
Department	Ariège
Arrondissement	Saint-Girons
Canton	Couserans Est
Government
• Mayor (2020–2026)	Alain Servat[1]
Area 1	98.34 km2 (37.97 sq mi)
Population  (2021)[2]	264
• Density	2.7/km2 (7.0/sq mi)
Time zone	UTC+01:00 (CET)
• Summer (DST)	UTC+02:00 (CEST)
INSEE/Postal code	09322 /09140
Elevation	560–2,803 m (1,837–9,196 ft) (avg. 746 m or 2,448 ft)
1 French Land Register data, which excludes lakes, ponds, glaciers > 1 km2 (0.386 sq mi or 247 acres) and river estuaries.

Ustou (French pronunciation: [ystu]; Occitan: Uston) is a commune in the Ariège department in southwestern France.

The commune of Ustou comprises several villages: Saint-Lizier, Le Trein, Sérac; and numerous hamlets, including: Escots, Bieille, Rouze.

Inhabitants of Ustou are called Ustouens.

• The Château de Mirabat, a Middle Ages castle, known to be in ruins in the 14th century, is in the communes of Seix, Oust and Ustou.

• Communes of the Ariège department