Green’s Dictionary of Slang

(US prison) a heavy lead collar or shackle fitted around a prisoner’s ankle; in pl., handcuffs.

1909		T.A. Dorgan in Zwilling TAD Lex. (1993) 61: Why Hal could wear an ‘Oregon boot’ and beat Tenney at first.
1912		D. Lowrie My Life in Prison 292: I have seen a mere boy [...] not only wearing an ‘Oregon boot,’ but shackled and handcuffed also.
1924		G. Henderson Keys to Crookdom 412: Oregon boot. Heavy steel manacle fastened to one ankle.
1931		Irwin Amer. Tramp and Und. Sl. 139: Oregon Boot.–A heavy steel manacle worn on the ankle and foot to prevent escape, and perhaps first used in Oregon. A ball and chain.
1949		Monteleone Criminal Sl. (rev. edn).
1954		J. Steinbeck Sweet Thursday (1955) 132: He’s a gone goose. He got a born-on Oregon boot. [Ibid.] 255: Oregon boots, handcuffs.
1970		(con. 1910s) Gaddis & Long Panzram (2002) 64: A prisoner whose rheumatic ankle had swelled to a huge size under the steel clamp of an Oregon boot [etc.].