O
- (Uman-Fonuweisom Municipality) Osan
- (Paata-Tupunion Municipality) Onas
- (Weno Municipality) Or
- (Parem Municipality) Oan
- (Uman-Fonuweisom Municipality) Ocha
- (Nomwin Municipality) Oiman
- (Weno Municipality) Okko
- (Pingelap Municipality) Onaf
- (Pwene Municipality) Onomue
- (Uman-Fonuweisom Municipality) Onaram
- (Oneop Municipality) Oneop
- (Moch Municipality) Oninuk
- (Siis Municipality) Onnang
- (Fanif Municipality) Onongoch
- (Kuttu Municipality) Onupuku
- (Parem Municipality) Opun
- (Kuttu Municipality) Orin
- (Uman-Fonuweisom Municipality) Ow
- (Onou Municipality) Onou
- (Onou Municipality) Onou Village
- (Oneop Municipality) Oneop Village
- (Ulithi Municipality) Onoun