The United States Penitentiary, Thomson (USP Thomson), formerly Thomson Correctional Center, is a high-security federal prison located in Thomson, Illinois. It has an area of about and comprises 15 buildings. The facility is enclosed by a , 7000 volt electric fence surrounded by an additional exterior fence covered with razor wire. Thomson has eight cellhouses with a rated capacity of 2,100 beds—1,900 high-security SMU beds and 200 minimum-security beds at the onsite camp—and according to BOP officials, the potential to use some of its high-security rated capacity to house up to 400 ADX inmates. From its completion in 2001 to 2006, it remained empty. By 2009, only the minimum-security section housed prisoners.