Tibbets was always a military prison, holding some of the United States' most dangerous criminals. Over time, the prison became more advanced, utilizing robotic wardens and utility robots to maintain the structure, especially as the war with China in the 2070s and the annexation of Canada began to drain personnel from the United States. It was designed to hold 636 prisoners at full capacity. As of 2253, it holds much more than that - but when the dust and ash settles after the catastrophic attack at the prison, there will be enough prisoners running from the shattered prison walls to pose a threat to the wasteland.