The Federal Detention Center (FDC Philadelphia) is a United States Federal prison in Center City, Philadelphia, Pennsylvania which holds male and female inmates prior to or during court proceedings, as well as inmates serving brief sentences. It is operated by the Federal Bureau of Prisons, a division of the United States Department of Justice. The jail, across from the William J. Green Jr. Federal Building, is on a 1-acre (0.40 ha) site the southwest corner of Arch Street and 7th Street, across from the African American Museum in Philadelphia and in the Independence Mall area. The jail is 12 stories tall. It has 628 cells for United States Marshal Service pre-trial inmates, primarily from the Eastern District of Pennsylvania, the District of New Jersey and the District of Delaware. Federal Detention Center Philadelphia is also a United States Parole Commission Revocation Site. 120 prisoners, already sentenced, serve as staff. The prison is connected to a tunnel that allows people to travel to and from the James A. Byrne United States Courthouse..