Administration officials are expected to visit the near-empty, top security Thomson Correctional Center, west of Chicago in the next day or so.
President Obama has pledged to close the Guantanamo Bay camp by 22 January.
Reports about relocating inmates come a day after plans were announced to try five men over the 9/11 attacks.
The Thomson prison, built by Illinois state in 2001 with 1,600 maximum security cells, has been dogged by budget problems, AP news agency reports.
'Safety and security'
Officials suggest the Federal Bureau of Prisons could buy the Thomson site and lease part of it to the Department of Defense to house Guantanamo inmates.