The Patterson River is a partly man-made urban river of the Port Phillip catchment in the Australian east coast state of Victoria, located in the outer southeastern suburbs of the Greater Melbourne region. Under the name "Patterson", it is the shortest river in Victoria at only 5 km (3.1 mi) in length, although its main stem tributary and de facto upper section, the Dandenong Creek, is over 53 km (33 mi) long.

Victoria is a state in southeastern Australia. It is the second-smallest state, with a land area of 227,444 km2 (87,817 sq mi); the second-most-populated state, with a population of over 6.7 million; and the most densely populated state in Australia. Victoria is bordered by New South Wales to the north and South Australia to the west and is bounded by the Bass Strait to the south, the Great Australian Bight portion of the Southern Ocean to the southwest, and the Tasman Sea to the southeast. The state encompasses a range of climates and geographical features from its temperate coastal and central regions to the Victorian Alps in the northeast and the semi-arid northwest.