The 21 month-sentence will be in addition to the eight-year sentence Greig is currently serving at a Minnesota prison after being convicted in 2012 of identity fraud and harboring a fugitive.
Greig spent 16 years on the run with Bulger while he was a fugitive and last September was indicted for Criminal contempt for refusing to testify to a grand jury about whether other people helped the couple hide.
The 64-year-old former dental hygienist and dog groomer fled Boston with Bulger in 1995 and was arrested with the gangster in 2011. The two had been living in a rent-stabilized apartment in Santa Monica under the names Carol and Charlie Gasko.
John Tlumacki / The Boston Globe / Getty
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In February, Greig pleaded guilty to the criminal contempt charge. She had initially pleaded not guilty before reversing her plea.
On June 24, the personal effects of Bulger and Greig will be put up for auction in Boston in an auction held by the U.S. Marshals Service.
Proceeds from the auction will be distributed between the families of 19 people authorities believe Bulger killed, according to a Department of Justice statement – although he was convicted of murdering only 13 people.
"Our goal is to maximize the proceeds of the auction to compensate the victims of Bulger's brutal crimes," U.S. Marshal John Gibbons said in a statement.