The river was named the 'Riviere des Francais' by the French Scientific Expedition in 1803 led by Nicolas Baudin. Early settlers called it the 'French River'. The explorer Dr Alexander Collie wrote down the name of the river as 'Kal-gan-up' in April 1831. The name Kalganup is thought to be the Noongar word for 'place of many waters'. Kalganup is also thought to mean 'place of fishes' and there are still the remains of Aboriginal fish traps to prove the point.