Abramoff, 51, was released Tuesday from the minimum-security federal prison camp in western Maryland where he had been confined since November 2006 for fraud, corruption and conspiracy convictions, spokesman Edmond Ross said.
Abramoff was moved to a residential re-entry center, or halfway house, in a region encompassing much of Maryland, Delaware, West Virginia and the District of Columbia, Ross said. He said he didn't know the location of the halfway house. Calls to the agency's Community Correctional Management section, which oversees halfway houses, weren't immediately returned.
Abramoff's scheduled release date is Dec. 4, Ross said. He said Abramoff could spend the last two to three weeks of his sentence in home confinement.
The Bureau of Prisons has no home address for Abramoff, spokeswoman Felicia Ponce said.
Abramoff was sentenced in 2006 to nearly six years for a fraudulent Florida casino deal. He got a four-year sentence in 2008 for conspiring to defraud the U.S., corrupting public officials and defrauding his clients in a separate case.
Ross said that unless a judge orders such sentences to run concurrently, the shorter sentence is normally subsumed by the longer one.
"It's usually a package deal, just for judicial economy purposes," he said.
Other factors, such as time off for good behavior, can further reduce an inmate's time served, Ross said.
As part of his plea deal, Abramoff cooperated in a long-running Justice Department investigation that led to the convictions of former Rep. Bob Ney, R-Ohio, former Deputy Interior Secretary J. Steven Griles and several top Capitol Hill aides.
Although he has expressed remorse, Abramoff also cooperated with the author of a 2008 book, "The Perfect Villain: John McCain and the Demonization of Lobbyist Jack Abramoff," in which he blamed Sen. John McCain, R-Ariz., for making him the fall guy.
"I never expected that I would have to go to prison until it became clear that the media could not allow this play to close without the hanging of the villain," Abramoff says in the book by Boston journalist Gary Chafetz.
He is the subject of a documentary film, "Casino Jack," released this year. A fictionalized version, "Casino Jack and the United States of Money," starring Kevin Spacey, is in the works.