Spa is a municipality of Belgium. It lies in the country's Walloon Region and Province of Liège. It is situated in a valley in the Ardennes mountain chain, some 35 km (22 miles) southeast of Liège, and 45 km (28 miles) southwest of Aachen. As of 1 January 2006, Spa had a total population of 10,543. The total area is 39.85 km², giving a population density of 265 inhabitants per km².