James Thomas said Kilpatrick was moved from the Oaks Correctional Institution in Manistee, Mich., to a low-security federal prison in Milan, The Detroit News reported.
Thomas said Kilpatrick sought the transfer because he would be able to prepare for his federal trial using a prison computer and a better library.
"The living conditions are substantially better," Harold Gurewitz, a criminal lawyer in Detroit, told the News. "It's not as crowded. It's cleaner. The food is much better. If I had a client who was going to be detained for a significant period of time, I would rather he would be there."
Kilpatrick was sentenced in May to up to five years for violating probation. He was indicted earlier this month on fraud and tax charges.
In Milan, one of Kilpatrick's fellow inmates is Umar Farouk Abdulmutallab, the Nigerian who allegedly used explosive underwear in an attempt to blow up a plane on Christmas Day. The facility, on 300 acres near Ann Arbor, has horseshoe pits and tennis courts.