The Department of Corrections says fighting broke out about 8 p.m. Saturday during an outdoor recreation period.
Several inmates received minor injuries, but the DOC did not elaborate. It says the cause of the fighting isn't known.
The four units known as the West Complex are on lockdown through the weekend while staff conducts an investigation. Visiting on Sunday has been canceled.
The media statement didn't specify how many inmates are affected. The entire prison houses about 2,200 offenders.