 The earliest form of the park was established in 1931 as the Three Brothers Mountain Reserve to prevent overgrazing, and eventually this became the three brothers game reserve in 1936.In 1941, the park was formed as Three Brothers Mountain Park, a Class A Provincial Park.The park was soon thereafter named in memory of Ernest Callaway Manning, Chief Forester of British Columbia from 1936 to 1941 (not to be confused with Ernest C. Manning, Premier of Alberta from 1943 to 1968).