Barrios de Massachusetts O

• Oak Grove (50)
• Oak Grove-Pine Banks (13)
• Oak Hill (28)
• Oak Island (19)
• Oak Square (21)
• Oakland Vale (15)
• Outer Fitchburg/Leominster (22)
• Outer Quincy/Milton/Randolph (18)
• Outer Route 1 South (44)
• Outlying Quincy-Milton (31)