Les Collines-de-l'Outaouais (, "The hills of the Outaouais") is a regional county municipality in the Outaouais region of western Quebec, Canada. The region nearly encircles the City of Gatineau, which is to the south. Its administrative seat is in Chelsea, Quebec.
It was created in January 1991 when the Communauté régionale de l'Outaouais (Outaouais Regional Community) was split into Les Collines-de-l'Outaouais RCM and the Communauté urbaine de l'Outaouais (Outaouais Urban Community, now City of Gatineau). The region is home to the majority of Gatineau Park. It is bisected by the Gatineau River which flows from north to south. The Ottawa River forms the southwestern boundary.
There are six subdivisions within the RCM:
Source: 2021 Census
Highways and numbered routes that run through the municipality, including external routes that start or finish at the county border: