Barrios de Illinois O

• O'Hare (11)
• Old Farm (3)
• Old Irving Park (30)
• Old Town (144)
• Old Town Chicago (2)
• Old Towne (5)
• Outer Loves Park/Machesney Park (14)
• Outer Northwest Rockford (26)
• Outer Rock Island/Moline (12)
• Outer South Rockford (21)
• Overlook (1)