The reservists from Chicago-area Second Battalion, 24th Marine Regiment reunited with their families Saturday afternoon.
Their reception was so large it had to be held at the Allstate Arena in Rosemont.
Twelve of the unit's members were killed during their deployment and about 120 were injured.
The unit had more than 70 police officers, including several from the Chicago Police Department. The battalion earned the nickname "Mad Ghosts" from Iraqi insurgents who said the Marines seemed to never sleep and to be everywhere.
The unit of about 1,100 reservists is made up of five companies, including two based in Wisconsin and one in Iowa.