city, Hautes-Alpes département, Provence-Alpes-Côte d'Azur région, southeastern France. Briançon lies at the confluence of the Durance and Guisanne rivers. Its location at a crossing point for commerce across the Alps made the city important historically. The upper city preserves 17th-century fortifications designed by Sébastien Le Prestre de Vauban; the lower city extends along both banks of the Durance. Military activity connected with the city's location near the frontier with Italy has long held first place in the city's economic life; it is also known, however, as a curative resort, with numerous sanatoriums. Pop. (1999) 10,737; (2005 est.) 12,100.