Barrios de Missouri O
- O'Fallon Park (1)
- O'Fallon St Charles (51)
- Oak Meyer Gardens (2)
- Oak Park Northwest (7)
- Oak Park Southeast (6)
- Oak Park Southwest (5)
- Oakville (5)
- Old Shoe Factory District (2)
- Old Westport (6)
- Oldham Farms (5)
- Ott-Chrisman (3)
- Outer North Springfield (24)
- Outer Southeast Springfield (27)
- Outer Southwest Springfield (54)