The Abraham Lincoln Brigade refers to volunteers from the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 who served in the Spanish Civil War

Spanish Civil War

The Spanish Civil WarAlso known as The Crusade among Nationalists, the Fourth Carlist War among Carlists, and The Rebellion or Uprising among Republicans. was a major conflict fought in Spain from 17 July 1936 to 1 April 1939...

 in the International Brigades

International Brigades

The International Brigades were military units made up of volunteers from different countries, who traveled to Spain to defend the Second Spanish Republic in the Spanish Civil War between 1936 and 1939....

. They fought for Spanish Republican

Second Spanish Republic

The Second Spanish Republic was the government of Spain between April 14 1931, and its destruction by a military rebellion, led by General Francisco Franco....

 forces against Franco

Francisco Franco

Francisco Franco y Bahamonde was a Spanish general, dictator and head of state of Spain from October 1936 , and de facto regent of the nominally restored Kingdom of Spain from 1947 until his death in November, 1975...

 and the Spanish Nationalists.

As time went on, the name Abraham Lincoln Brigade became used loosely, in the United States, as shorthand to describe any unit with an American component. Volunteers from the United States also served with the Canadian Mackenzie-Papineau Battalion

Mackenzie-Papineau Battalion

The Mackenzie–Papineau Battalion or Mac-Paps were a battalion of Canadians who fought as part of the XV International Brigade on the Republican side in the Spanish Civil War. Except for France, no other country gave a greater proportion of its population as volunteers in Spain than Canada. The...

, the Regiment de Tren (transport), and the John Brown Anti-Aircraft Battery.