The Arroyo Seco stream begins at Red Box near Mount Wilson in the San Gabriel Mountains and proceeds through steep mountain canyons for until it enters the urban plain of Southern California at the Jet Propulsion Laboratory. The stream, largely channelized south of Devil's Gate Dam, proceeds in the Arroyo Seco canyon for more: through Pasadena, South Pasadena and Northeast Los Angeles to the confluence with the Los Angeles River near Elysian Park, Chinatown and downtown Los Angeles.