Formed by the confluence of the Dandenong Creek and the Eumemmerring Creek, southwest of approximately south-east of Melbourne, the man-made Patterson River was constructed in 1878 to assist the drainage of swamplands located in what is now the suburb of . The urban channel flows generally southwest before emptying into Beaumaris Bay, an eastern bay within Port Phillip at the river mouth, near Carrum. The waterway provides access to canals in the suburbs of Patterson Lakes, Carrum and Bonbeach; and descends over its course.