The town, which is located about 90 km (56 mi) from Turin at the intersection of four valleys, is surrounded by mountains, including several whose peaks surpass 3,000 m (9,800 ft).
The historic center is set back and elevated (Borgo Vecchio), while the new part of town was built around the train station (Borgo Nuovo). The town has grown thanks to activities related to customs, logistics, and tourism; as a result, it has incorporated some neighboring villages and thus is one of the largest towns in the Susa Valley.
The municipality of Bardonecchia contains the frazioni (subdivisions, mainly villages and hamlets) Les Arnauds, Melezet, Millaures, Le Gleise, Beaulard, Grange Horres, La Rho and Rochemolles.