United Airlines, headquartered in Chicago, Illinois, was founded on April 6, 1926 and began operations on March 28, 1931.

List of United Airlines Offices:

Antigua and Barbuda
Argentina – Buenos Aires
Australia (Reservation)
Australia (Service Center)
Bahamas
Bahrain – Umm Al Hassam
Bangladesh – Dhaka
Bangladesh – Motijheel
Belgium (Reservation)
Belgium (Service Center)
Belize – Belize
Bermuda
Brazil – all cities
Brazil – Rio de Janeiro
Brazil – São Paulo
Cayman Islands
Chile – Santiago
China – For all cities in China (except Hong Kong)
China – Hong Kong
Colombia – Local 112 Torre B (Teleport), Santa Fe de Bogota
Colombia – Torre A Local 2, Santa Fe de Bogota
Costa Rica – Pavas
Costa Rica – San Jose
Costa Rica – San Pedro
Denmark
Dominican Republic – Avenida San Vicente de Paul esq. Carretera Mella
Dominican Republic – Edificio In Tempo, Evaristo Morales
Ecuador – Conjunto
Ecuador – Piso
Egypt
El Salvador – San Miguel
El Salvador – San Salvador
Federated States of Micronesia – Chuuk (Truk)
Federated States of Micronesia – Kosrae
Federated States of Micronesia – Pohnpei
Federated States of Micronesia – Yap
Finland
France (Mileage plus service ctr)
France (Reservation Off)
Germany (Res. Office)
Germany (Mileageplus Service Ctr)
Greece
Guam – Tamuning
Guam
Guatemala – Nivel 1
Guatemala – 18 Calle 5-56 Zona 10
Honduras – San Pedro Sula
Honduras – Tegucigalpa
India – Chennai
India – Delhi
India – Kolkata
India – Mumbai
Indonesia – Jakarta
Ireland (Mileageplus Service Center)
Ireland (Reservation Office)
Israel – Tel Aviv
Italy – Milan (Mileageplus Service Center)
Italy – Milan (Reservation Office)
Italy – Rome (Mileageplus Service Center)
Italy – Rome (Reservation Office)
Jamaica
Japan (Reservation)
Japan (Mileageplus Service)
Jordan
Kuwait – Kuwait City
Luxembourg (Mileageplus Service Center)
Luxembourg (Reservation Office)
Malaysia – Kuala Lumpur
Marshall Islands – Kwajalein
Marshall Islands – Majuro
Mexico – Aguascalientes
Mexico – Chihuahua
Mexico – Guadalajara
Mexico – Leon
Mexico – Merida
Mexico – Col. Antigua Mina La Totolapa, Mexico City
Mexico – Local 250A  Nivel Avenida, Mexico City
Mexico – Av. Paseo de la Reforma 250 Planta Baja (ground floor), Mexico City
Mexico – Mexico City (Mileageplus)
Mexico – Mexico City (Reservation)
Mexico – Monterrey
Mexico – Monterrey
Mexico – Querétaro
Mexico – San Luis Potosi
Mexico – Tampico
Mexico – Veracruz
Mongolia – Ulaanbaatar
Nepal – Kathmandu
Netherlands (Mileageplus service)
Netherlands (Reservation)
Netherlands Antilles – Aruba
Netherlands Antilles – Bonaire
Netherlands Antilles – Curaçao
Netherlands Antilles – St. Maarten
New Zealand (Mileageplus Service Ctr)
New Zealand (Reservation Office)
Nicaragua – Managua
Nigeria – Lagos
Northern Mariana Islands
Norway
Pakistan – Islamabad
Pakistan – Karachi
Pakistan – Lahore
Palau
Panama – Planta Baja
Paraguay – Asuncion
Peru – San Isidro
Philippines – Makati
Philippines – V.A. Rufino Street cor 6784 Ayala Avenue, Makati
Portugal
Puerto Rico
Qatar – Doha
Rota
Russian Federation – Moscow
Saudi Arabia – Dhahran/Dammam (Eastern Province)
Singapore – Singapore
South Africa – Johannesburg
South Korea – Chongro-gu, Seoul
South Korea – Jongro-gu, Seoul
Spain
Sri Lanka – Colombo
St. Kitts
St. Lucia
Sweden (Reservation Off.)
Sweden (Mileageplus Service Ctr)
Switzerland (Service Center)
Switzerland (Reservation Office)
Taiwan
Thailand – Bangkok
Trinidad and Tobago – Port of Spain
Turkey – Istanbul
Turks and Caicos
U.S. Virgin Islands
United Arab Emirates
United Kingdom
Uruguay – Montevideo
Venezuela – El Rosal
Vietnam – Hanoi
Vietnam – Ho Chi Minh,

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