Mount Rosseau is a mountain on Vancouver Island, British Columbia, Canada, located 43 km (27 mi) southwest of Courtenay and 23 km (14 mi) south of Mount Albert Edward.

The most western summit of the massif is Mount Septimus.

Mount Rosseau is part of the Vancouver Island Ranges which in turn form part of the Insular Mountains.

[1] The BC Geographical Names Information System records the origin of Mt Rosseau's name:[2] [Mount Rosseau is named after] Ralph Rosseau, a widely known and respected elementary school principal in Port Alberni and a noted mountaineer; killed in a climbing accident on Mount Septimus 3 July 1954.

(obituary & photograph in West Coast Advocate, 8 July 1954, file T.1.43) Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office Mount Septimus has three established access routes: