The capital of Léman département was Geneva. The département was subdivided into the arrondissements of Geneva, Bonneville and Thonon-les-Bains. Its territory corresponds with the present Swiss canton of Geneva and parts of the present French départements Ain and Haute-Savoie.
After the final defeat of Napoleon Bonaparte in 1815, the former republic of Geneva became a Swiss canton, and Savoy was returned to the Kingdom of Sardinia. The area around Gex returned to Ain département.