The Oregon Boot (or Gardner Shackle) was the modern equivalent of the medieval ball and chain shackle. The purpose of the Oregon Boot was to restrict quick movements and was used on prisoners during outside work duty from the mid nineteenth century.
J.C. Gardner was the warden at the Oregon Penitentiary and patented his invention in 1866. J.C Gardner was keen to ensure receipt of his royalties. The Oregon Boot consisted of a heavy iron leg cuff secured about the ankle and held in place by a stirrup like attachment passing under the heel of the boot and on the end of the chain was a heavy metal ball. The Oregon Boot was attached to one leg only and caused the prisoner to drag their foot. Wearing the shackle for extended periods of time caused extreme physical damage and many prisoners ended up bedridden in extreme pain. The boot was used regularly up until 1878 then it seemed to be used as a punishment only with the last recorded use in 1939.
The term Chain Gang was used to describe prisoners tethered together with chains.