Des Plaines is a city in Cook County, Illinois, United States. As of the 2010 census, the city had a population of 58,364. It is a suburb of Chicago and is just north of O'Hare International Airport. It is located on, and named for, the Des Plaines River, which runs through the city just east of its downtown area. Des Plaines is the home of the first franchised McDonald's opened by Ray Kroc in 1955, which is preserved as a museum on Lee Street, north of downtown.