Judge Thomas Lipps announced his decision after reviewing evidence presented over four days of testimony against Trent Mays, 17, and Ma'Lik Richmond, 16, who were tried as juveniles, Xinhua reported.
The victim was not present when the ruling was read.
Mays was sentenced to a minimum of two years in a juvenile correctional facility, while Richmond was given a sentence of a minimum of one year, but like Mays he could be placed in detention until he is 21.
Mays was also found guilty of disseminating nude images of a minor.
The trial gained national attention for lurid text messages, cell phone pictures and videos, and social media posts surrounding the sexual abuse of the victim girl.
Mays and Richmond were accused of raping the allegedly drunk girl during heavy partying in August 2012.
The judge said many of the documents and text messages were "profane" and "ugly" and the case showed alcohol "as a particular danger to our teenage youth".
Both Mays and Richmond apologised to the victim and her family in the court.