Hawaii: Handgun 10 rounds
DC = 10
New Jersey = 15
Illinois: Some local governments have magazine capacity limits for both pistols and long guns, including Chicago (12 rounds), Oak Park (10 rounds), Aurora (15 rounds), and Cook County (10 rounds).
Maryland: Illegal to sell or manufacture magazines with a capacity of greater than 20 rounds within Maryland. However, possession of magazines greater than 20 rounds is legal
Massachusetts: Illegal to possess magazines of over 10 rounds capacity unless manufactured prior to 09/13/1994, and one has a LTC-A. Does not apply to tubular and .22 rimfire magazines.