Spa is a municipality of Belgium. It lies in the country's Walloon Region and Province of Liège. It is situated in a romantic valley amid hills which form part of the Ardennes 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.
As the famed site of healing hot springs, Spa has been frequented as a watering-place since as early as the 14th century. Though other sources of healing hot mineral springs have become famous throughout the world, it is the town of Spa which has become eponymous with any place having a natural water source that is believed to possess special health-giving properties, as a spa.
In 1918, the German Army established its principal Headquarters in Spa, and it was from here that the delegates set out for the French lines to meet Marshal Foch and sue for peace in the consultations leading up to the Armistice which ended the First World War.
Agatha Christie's fictional detective Hercule Poirot was born in Spa.