Société de transport de l'Outaouais (STO) is the transit service of the Outaouais region of Quebec. It operates conventional services and the Rapibus, a bus rapid transit service, in Gatineau, Quebec, including the districts of Hull, Aylmer, Gatineau, Buckingham and Masson-Angers. STO provided limited service to Chelsea and Cantley until June 2015 when Transcollines began operations in the Collines de l'Outaouais MRC. STO is located on the Quebec-side of Canada's National Capital Region, and operates several bus routes through Downtown Ottawa, Ontario.