There were two battalions of American volunteers fighting for Republican Spain, the Abraham Lincoln Battalion and the George Washington Battalion. Losses were heavy, so the two were merged and came to be known as the Lincoln-Washington Battalion. In looking back they came to be known as the Lincoln Brigade, though that wasn’t actually correct.
There is a Lincoln Center in Havana which I believe is dedicated to the Lincoln Brigade which fought on the side of the communists in the Spanish Civil War.