US-made Rolls-Royce Silver Ghost and Rolls-Royce Phantom I were built at the
Springfield-plant in Massachusetts. In Springfield the Knox Automobile Co,
founded in 1901 by Harry Knox, from a meagre beginning with a one-cylinder
car had developed to a motor car maker offering cars with 4- and 6-cylinder
engines, some of which were entered successfully in competitive events.
Although the product range was widened to cover the truck-market, too, the
manufacturer couldn’t stand the pressure from the competitors from Detroit.
Knox closed down in 1922.