German Mills Creek is a river in the municipalities of Markham, Richmond Hill, Toronto and Vaughan in the Greater Toronto Area of Ontario, Canada. It is part of the Great Lakes Basin and is a left tributary of the East Branch Don River. It originates in Vaughan (near Bathurst Street and the King–Vaughan Town Line), flows south through Richmond Hill and Markham, and empties into the East Branch Don River in the East Don Parklands in Toronto, south of Steeles Avenue between Bayview Avenue and Leslie Street. It is part of a number of streams, swamps and swales located near the Oak Ridges Moraine. The creek's approximate length is 10 kilometres (6 mi).