antic Ocean Atlantic Ocean
North Channel Atlantic Ocean
Northeast Providence Channel Atlantic Ocean
Northern Epirus Albania; Greece
Northern Grenadines Saint Vincent and the Grenadines
Northern Ireland United Kingdom
Northern Rhodesia Zambia
North Island New Zealand
North Korea Korea, North
North Pacific Ocean Pacific Ocean
North Sea Atlantic Ocean
North Vietnam Vietnam
Northwest Passages Arctic Ocean
North Yemen (Yemen Arab Republic) Yemen
Norwegian Sea Atlantic Ocean
Nouakchott [US Embassy] Mauritania
Novaya Zemlya Soviet Union
Nuevo Laredo [US Consulate] Mexico
Nyasaland Malawi

Oahu United States
Oaxaca [US Consular Agency] Mexico
Ocean Island (Banaba) Kiribati
Ocean Island (Kure Island) United States
Ogaden Ethiopia; Somalia
Oil Islands (Chagos Archipelago) British Indian Ocean Territory
Okhotsk, Sea of Pacific Ocean
Okinawa Japan
Oman, Gulf of Indian Ocean
Ombai Strait Pacific Ocean
Oporto [US Consulate] Portugal
Oran [US Consulate] Algeria
Oresund (The Sound) Atlantic Ocean
Orkney Islands United Kingdom
Osaka-Kobe [US Consulate General] Japan
Oslo [US Embassy] Norway
Otranto, Strait of Atlantic Ocean
Ottawa [US Embassy] Canada
Ouagadougou [US Embassy] Burkina
Outer Mongolia Mongolia

Pagan Northern Mariana Islands
Palau Pacific Islands, Trust Territory of the
Palawan Philippines
Palermo [US Consulate General] Italy
Palk Strait Indian Ocean
Palma de Mallorca Spain
[US Consular Agency]
Pamirs China; Soviet Union
Panama [US Embassy] Panama
Panama Canal Panama
Panama, Gulf of Pacific Ocean
Paramaribo [US Embassy] Suriname
Parece Vela Japan
Paris [US Embassy, US Mission to France