The municipality is composed of the Town of Soignies together with the villages of Casteau, Chaussée-Notre-Dame-Louvignies, Horrues, Neufvilles, Naast and Thieusies. Casteau is known worldwide because SHAPE, the military headquarters of NATO, has been based at the village since 1967.
The name of Soignies comes from the Latin word suniacum, which means "on the Senne". The spring of the Senne is near Soignies. After Soignies, the river passes through Brussels.
Soignies is also well known for its blue limestone (from the Carrières du Hainaut) and its glass industry (Durobor).