WordNet (r) 3.0 (2006):

labor camp
    n 1: a penal institution for political prisoners who are used as
         forced labor [syn: labor camp, labour camp]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "labor camp":
   POW camp, bastille, black hole, borstal, borstal institution,
   bridewell, brig, cell, concentration camp, condemned cell,
   death cell, death house, death row, detention camp, federal prison,
   forced-labor camp, gaol, guardhouse, house of correction,
   house of detention, industrial school, internment camp, jail,
   jailhouse, keep, lockup, maximum-security prison,
   minimum-security prison, oubliette, pen, penal colony,
   penal institution, penal settlement, penitentiary, prison,
   prison camp, prisonhouse, reform school, reformatory,
   sponging house, state prison, stockade, the hole, tollbooth,
   training school