Oo (25/25)

Oberhollabrunn, 1805 *	Ocean Pond	Oenophyta, 457 f.Kr.	Ohod, 625 *
Okinawa, 1945 *	Olmütz, 1758 *	Oltenita, 1853 *	Olustee, 1864 *
Omdurman, 1898 *	Oostende, 1601-04 *	Oporto, 1809 *	Oran I, 1509 *
Oran II, 1940 *	Orchard Knob-Indian Hill, 1863 *	Orchomenus, 85 f.Kr. *	Oriskany, 1777 *
Orléans, 1428-29 *	Ostindien, 1941-42	Ostroleka, 1831 *	Oswego, 1756 *
Otterburn, 1388 *	Otumba, 1520 *	Oudenarde, 1708 *	Ourcq-floden, 1914 *
Ourique, 1139 *