[3][4][5] The name of Waterloo was mentioned for the first time in 1102 designating a small hamlet at the limit of what is today known as the Sonian Forest, along a major road linking Brussels, Genappe and a coal mine to the south.

During the late 18th century, whilst the region was under the rule of the Holy Roman Empire, a period of unrest marked the wake of the 1789 French Revolution.

In 1794, the French invaded, bringing an end to the region's Ancien Régime, encompassing the monasteries, their official record-keeping, and the privileges of the nobility.

Some municipalities, including Waterloo, became part of the Dyle department, which became the province of Brabant Méridional in 1815 under Dutch rule, following the defeat of Napoleon.

Nearly one-fifth of the current registered population (5,640 inhabitants) is non-Belgian; many such residents work for institutions or companies in Brussels, a political centre of the European Union.

There is a Carrefour hypermarket in Mont-Saint-Jean, a Delhaize store, an Ibis Hotel, several BNP Paribas Fortis branches, office parks to the east of the town.

In 1831, approximately 250 hectares of land in the Sonian Forest was acquired by Ferdinand De Meeus, a member of the Belgian nobility, who bestowed the name "Argenteuil" to the estate.

The first "Château d'Argenteuil", built in 1835 was destroyed by a fire in 1847, and rebuilt between 1856 and 1858 using a design by Belgian architect, Jean-Pierre Cluysenaar, and extensive landscaping of the surrounding lands by Édouard Keilig.

In the 1920s the De Meeûs family incorporated the estate into the "Domaine d'Argenteuil SA", and in 1929 sold 145 hectares of the land to American businessman, William Hallam Tuck.

Tuck and his wife, Belgian heiress, Hilda Bunge, commissioned New York architect, William Delano, to design the second major residence on the Argenteuil estate, the "Château Bellevue".

In 1940, the Château d'Argenteuil, 20 hectares of its surrounding lands and a farm were sold to a community of Carmelite Sisters in exchange for their properties in Uccle, Brussels.

From 1961 it was the official residence of the Belgian royal family, King Leopold III and his wife Princess Lilian, up until her death in 2003.

During discussions on the Treaty establishing a Constitution for Europe there were proposals to turn the château into a residence for the mooted position of the President of the European Union.

It was originally built in 1895 as the home of a French industrialist who had made his fortune in Mont-Saint-Jean, Waterloo following the opening of a chemical fertiliser plant in 1875.

[8] On 2 February 2018, the Belgian commune of Waterloo confirmed that former Catalonia president Carles Puigdemont had rented a villa and planned to establish his official residence there.