This list includes some of the territories and regions that may be harder to find on the global map of WWI combatants above.
Caribbean Netherlands (Curacao or Aruba): A colony of the Kingdom of the Netherlands, which remained neutral during the war.
Christmas Island (Australia): A colony of Great Britain, which entered the war in August 1914.
Cook Islands (Niue): A colony of Great Britain, which declared war on Germany on Aug. 4, 1914.
Falkland Islands (Great Britain or Argentina): A colony of Great Britain, which declared war on Germany on August 4, 1914; site of the Battle of the Falkland Islands on December 8. 1914.
Faroe Islands (Denmark): Part of the Kingdom of Denmark, which was neutral during the war.
French Guiana (France, Suriname, or Brazil): A colony of France, which entered the war in August 1914.
French Polynesia (France or Niue): A colony of France, which entered the war in August 1914.
Gaza Strip (Palestine not Israel): A territory of the Ottoman Empire, which entered the war as a Central Power in July 1914.
Gibraltar (Spain): A colony of Great Britain, which declared war against Germany on August 4, 1914; residents of the British colony established the Gibraltar Volunteer Corps for domestic defense.
Guadeloupe (France or Dominica): A colony of France, which entered the war in August 1914.
Holy See (Vatican City State): Never formally declared neutrality, though its publication of “Ad Beatissimi” on Nov. 1, 1914 and “Peace Note” on Aug. 1, 1917 could be considered proclamations; provided humanitarian aid during the war.
Kiribati (Fiji): A colony of Great Britain, which entered the war in August 1914; eligible islanders served with New Zealand forces.
Maldives (Sri Lanka): A protectorate of Great Britain, which declared war on Germany on August 4, 1914
Marshall Islands (Nauru): A colony of Germany, which entered the war on August 1, 1914; the islands were captured and occupied by Japan in 1914.
Martinique (France or Dominica): A colony of France, which entered the war in August 1914
Mauritius (Madagascar): A colony of Great Britain, which declared war on Germany on August 4, 1914
Mayotte (Madagascar): A colony of France, which entered the war in August 1914
Micronesia (Nauru): A colony of Germany, which entered the war on August 1, 1914; the islands were captured and occupied by Japan in 1914.
Northern Mariana Islands (Guam): A colony of Germany, which entered the war on August 1, 1914; the islands were captured and occupied by Japan in 1914.
Palau (Philippines): A colony of Germany, which entered the war on August 1, 1914; the islands were captured and occupied by Japan in 1914.
Pitcairn Islands (Niue): A colony of Great Britain, which declared war on Germany on August 4, 1914.
Réunion (Madagascar): A colony of France, which entered the war in August 1914
Saint Barthelemy (Anguilla): A colony of France, which entered the war in August 1914
Saint Helena (Angola): A colony of Great Britain, which declared war on Germany on August 4, 1914
Seychelles (Madagascar): A colony of Great Britain, which declared war on Germany on August 4, 1914
Somaliland (Republic of Somaliland): This de facto state was part of territory divided into British Somaliland (British colony) and Italian Somaliland (Italian colony) which supported the Allied Powers
South Georgia and the South Sandwich Islands (Argentina): An overseas territory administered by Great Britain, which declared war against Germany on August 4, 1914.
Timor-Leste (Indonesia): A colony of Portugal, which officially entered the war on March 9, 1916 after Germany's declaration.
Tokelau (Samoa): A colony of Great Britain, which entered the war in August 1914; awarded to New Zealand in the Treaty of Versailles.
Tuvalu (Samoa): A colony of Great Britain, which entered the war in August 1914. Eligible islanders served with New Zealand forces, including Kaipati, the only-known man from Tuvalu.
Wallis & Futuna (Fiji): Administered by New Caledonia, a colony of France; islanders are known to have fought in the war, though an approximate number continues to be calculated.