Barrios de Massachusetts O

• Oak Grove (20)
• Oak Grove-Pine Banks (7)
• Oak Hill (18)
• Oak Island (17)
• Oak Square (32)
• Oakland Vale (21)
• Outer Fitchburg/Leominster (16)
• Outer Quincy/Milton/Randolph (11)
• Outer Route 1 South (38)
• Outlying Quincy-Milton (25)