Reality Winner, 26, from the US state Georgia, on Thursday, was also sentenced to three years of supervised release and no fine, except for a $100 special assessment fee.
The crime carried a maximum penalty of 10 years, Xinhua news agency reported. Winner was a contractor with the US National Security Agency. She pleaded guilty in June to copying a classified report that detailed the alleged Russian government's efforts to penetrate a Florida-based voting software supplier.
The US authorities have never confirmed what exactly the report said, or identified the news organisation that received it, according to reports. Winner's attorneys called her a good person with an otherwise clean criminal record, and said that she suffers from depression and bulimia.
Russia has denied that it is government had any role in hacking the Democrats in 2016.