Few communes the size of Sainte Foy extend over such a vast area, or such a large difference in altitude. The commune covers over 11,000 hectares and spans a height difference of 2856m, from its lowest point at Viclaire at 890m to the summit of the Grande Sassière at 3746m.

It is bounded to the South by the river Isère (apart from a small area on the other side of the river), and to the north for 20 or so kilometers by the Italian border. This can be easily crossed by the two mountain passes, the Col du Mont and the Col du Rocher Blanc. To the east and west it is bounded by the "nants" (mountain streams) of Moulins and La Balme (or Nant Cruet).

Amongst the 100 or so hamlets that make up the commune is to be found Le Miroir (the mirror), a protected site. The origin of the name is debatable: some say it is a derivative of mourir (to die) reflecting the terrible epidemics and plagues that ravaged Europe in the Middle Ages. However, it is nicer to think that the beauty of this village, whose windows reflect the midday sun, earned it its pretty name. Le Miroir is renowned for it's colonnaded chalets, an attractive architectural feature with practical origins.

The use of such columns originated in the Italian Aosta valley. They support the roof overhang, which provides a covered area allowing dry air to circulate in the hay loft or wood store, and allowing the building's occupants to circulate from one floor to another sheltered from inclement weather.
Such chalets can also be seen in La Mazure, Montalbert, Le Baptieu, La Thuile, and Bonconseil (now Sainte Foy ski resort).