The municipality of Onex became an independent municipality in 1851 when the municipality of Onex-Confignon split into the two municipalities of Onex and Confignon.[3]
Geography
The municipality is on the left bank of the Rhône river.
The municipality has seven villages of Cressy - Marais, Evaux, Cité-Nouvelle, Gros-Chêne, Pré-Longet, Belle-Cour and Onex - village.