With attention focused on other aspects of immigration reform, the federal government has quietly gone on a massive immigrant prison building spree. Since 1999, the Bureau of Prisons has contracted for the operation of 13 for-profit private prisons located mostly in isolated towns far from the prying eyes of activists, prisoner’s families or attorneys. Five are located in Texas. Run by three private companies, these 13 “criminal alien requirement” prisons, as the BOP calls them, house one of America’s fastest-growing prison populations: immigrants in federal custody, many convicted for the crime of illegally crossing the border. The 13 facilities collectively house more than 25,000 immigrant prisoners at a cost to US taxpayers estimated at $1bn a year.