Calvas is a canton of the Province of Loja, Ecuador, located in the south of the province, bordering Paltas and Gonzanamá in the north, Quilanga and Espíndola in the east, Peru in the south, and Sozoranga in the west. It covers 851.2 km2 at an altitude of about 1,932 m. The total population is 26,042, and the capital city of the canton is Cariamanga.