Dyle was a department of the First French Empire in present-day Belgium. It was named after the river Dyle, which flows through the department. Its territory corresponded more or less with that of the Belgian province of Brabant, now divided into Walloon Brabant, Flemish Brabant and the Brussels-Capital Region. Its capital was Brussels.
The department came into existence on 1 October 1795, after the Southern Netherlands were occupied by the French. The department of Dyle was formed from the southern part of the Duchy of Brabant, part of the County of Hainaut, (Halle) and some smaller territories. See the 130 departments of the Napoleonic Empire.
- Brussels, cantons: Anderlecht, Asse, Brussels (4 cantons), Halle, La Hulpe, Sint-Martens-Lennik, Sint-Stevens-Woluwe, Uccle, Vilvoorde and Wolvertem.
- Leuven, cantons: Aarschot, Diest, Glabbeek, Grez, Haacht, Leuven (2 cantons), Tienen (2 cantons) and Zoutleeuw.
- Nivelles, cantons: Genappe, Herne, Jodoigne, Nivelles (2 cantons), Perwez and Wavre.
Its population in 1812 was 431,969, and its area was 342,848 hectares.