The Rapid River is a river in Sudbury District and Greater Sudbury in Northwestern Ontario, Canada. It begins at an unnamed marsh, at an elevation of 430 metres (1,411 ft) and just upstream of Osbourne Lake, in Unorganized Sudbury, Sudbury District. It travels south to its mouth at the Vermillion River at an elevation of 282 metres (925 ft), near the community of Val Thérèse in Greater Sudbury.