Barrios de Massachusetts O

• Oak Grove (32)
• Oak Grove-Pine Banks (13)
• Oak Hill (25)
• Oak Island (14)
• Oak Square (17)
• Oakland Vale (6)
• Outer Fitchburg/Leominster (28)
• Outer Quincy/Milton/Randolph (24)
• Outer Route 1 South (29)
• Outlying Quincy-Milton (24)