Below is a list of the Duchies of the Holy Britannian Empire from Game of Geass.
Imperial Homeland (Britannian Isles)[]
- Dominion of Anglia - England
- More to come..
- Dominion of Caerleon - Isle of Man
- More to come..
- Dominion of Ireland
- More to come..
- Dominion of Scotland
- More to come..
- Dominion of Wales
- More to come..
Area 1 (Canada)[]
- Grand Duchy of Alberta
- Grand Duchy of Britannian Columbia - British Columbia
- Duchy of Manitoba
- Duchy of New Brunswick
- Duchy of Newfoundland
- Duchy of Northumberland - Northwest Territories
- Duchy of Nova Scotia
- Duchy of Nunavut
- Grand Duchy of Ontario
- Grand Duchy of Quebec
- Duchy of Saskatchewan
- Grand Duchy of Vancouver
- Duchy of Yukon
Area 2 (Greenland and Iceland)[]
- Duchy of Arran - Qaasuitsup
- Duchy of Bradlaugh - Qeqqata
- Grand Duchy of Iceland
- Duchy of Quimper - Kujalleq
- Duchy of Snowdon - Northeastern Greenland
- Duchy of Turton - Sermersooq
Area 3 (Central America and Caribbean)[]
- Grand Duchy of Costa Rica
- Grand Duchy of Guatemala - Guatemala, Belize
- Duchy of Hispaniola - Haiti, Dominican Republic
- Duchy of Jamaica
- Duchy of Honduras - Honduras, El Salvador
- Duchy of Lucayan - The Bahamas, Turks and Caicos Islands
- Duchy of Nicaragua
- Duchy of Oryswell - Antigua and Barbuda, Barbados, Dominica, Grenada, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Anguilla, British Virgin Islands, Guadeloupe, Martinique, Montserrat, Saba, Saint Barthélemy, Saint-Martin, Sint Eustatius, Sint Maarten, United States Virgin Islands
Area 4 (Guianas)[]
- Duchy of Guyana - Guyana, Suriname, French Guiana
Area 5 (South Africa)[]
- Duchy of Angola
- Grand Duchy of Bechuanaland - Botswana
- Grand Duchy of Johannesburg - South Africa, Lesotho and Eswatini (Swaziland)
- Duchy of Madagascar
- Duchy of Maputo - Mozambique and Malawi
- Duchy of Rhodesia - Zimbabwe
- Duchy of Windhoek - Namibia
Area 6 (Australia)[]
- Duchy of Adelaide - South Australia
- Duchy of Darwin - Northern Territory
- Grand Duchy of Kingsland - Queensland
- Grand Duchy of Melbourne - Victoria
- Grand Duchy of Sydney - New South Wales, Australian Capital Territory, Jervis Bay Territory
- Duchy of Perth - Western Australia
- Duchy of Tasmania
Area 7 (New Zealand)[]
- Grand Duchy of Auckland
- Grand Duchy of Canterbury
- Duchy of Chatham
- Duchy of Gisborne
- Grand Duchy of Hawkesbay - Hawke's Bay
- Grand Duchy of Manawatū-Whanganui
- Grand Duchy of Marlborough
- Grand Duchy of Nelson
- Duchy of Northland
- Grand Duchy of Otago
- Grand Duchy of Plentysbay - Bay of Plenty
- Grand Duchy of Southland
- Duchy of Taranaki
- Grand Duchy of Waikato
- Grand Duchy of Wellington
- Duchy of Westland - West Coast
Area 8 (Papua New Guinea and Pacific Islands)[]
- Duchy of Arawa - New Guinea Islands Region
- Duchy of Lae - Momase Region
- Grand Duchy of Moresby - Southern Region
- Duchy of Mount Hagen - Highlands Region
- Duchy of Pacifica - British Pacific Islands
Area 9 (Falkland Islands)[]
- none