Historically and culturally, the commune is in Lomagne, a former district of the Ancient provinces of France called Gascogne having the title of a viscounty, nicknamed “ French Tuscany.

Exposed to an altered oceanic climate, it is drained by the Garonne, the Arrats and various other small rivers.

The commune has a remarkable natural heritage: a Natura 2000 site (“Garonne, Ariège, Hers, Salat, Pique et Neste”), a protected area (the “course of the Garonne, of the Aveyron, Viaur and Tarn) and four Natural zone of ecological, fauna and flora interest|natural zones of ecological, fauna and flora interest.

Made up of three ancient parishes (Saint-Martin de Christinag, Saint-Jean de Castel and Saint-Loup forming a priory), the parish of Saint-Loup depended on the jurisdiction of Auvillar.

Note also the ephemeral parish of Saint-Michel-de-Lastours and its bastide built near an artificial mound on the Agre plateau.