The Collaborative International Dictionary of English v.0.48:

hoosegow \hoosegow\, hoosgow \hoosgow\n. [from Mexican Sp.
   jusgado jail, from Sp. juzgado court of justice.]
   a jail. [U. S. western slang]
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

hoosgow
    n 1: slang for a jail [syn: hoosegow, hoosgow]