O
- (Eure-et-Loir) Orébin
- (Loiret) Oinville
- (Eure-et-Loir) Oisème
- (Indre) Onzay-Palluau
- (Eure-et-Loir) Orlu
- (Loir-et-Cher) Oigny
- (Loiret) Orville
- (Indre) Orville
- (Loiret) Oison
- (Loir-et-Cher) Ouzouer-le-Doyen
- (Cher) Osmery
- (Loiret) Ouzouer-sous-Bellegarde
- (Indre) Obterre
- (Loir-et-Cher) Orçay
- (Eure-et-Loir) Orrouer
- (Eure-et-Loir) Oinville-Saint-Liphard
- (Cher) Osmoy
- (Cher) Orcenais
- (Eure-et-Loir) Oinville-sous-Auneau
- (Loiret) Ouzouer-des-Champs
- (Loir-et-Cher) Oisly
- (Loiret) Orveau-Bellesauve
- (Loiret) Ondreville-sur-Essonne
- (Loiret) Oussoy-en-Gâtinais
- (Indre) Oulches
- (Eure-et-Loir) Ozoir-le-Breuil
- (Eure-et-Loir) Oysonville
- (Eure-et-Loir) Ouarville
- (Eure-et-Loir) Ollé
- (Eure-et-Loir) Ouerre