Which two U.S. cavalry regiments known as Buffalo Soldiers fought in Cuba?

The two U.S. cavalry regiments known as Buffalo Soldiers that fought in Cuba were the 9th and 10th Cavalry. These African American regular Army units were created after the Civil War and became famous for their frontier service in the American West.

During the Spanish-American War in 1898, the 9th and 10th Cavalry served in Cuba as part of the U.S. Army cavalry division commanded by Joseph Wheeler. Because of the terrain and Spanish defenses, the cavalry often fought dismounted, using rifles rather than charging on horseback.

Both regiments took part in the fighting around Santiago de Cuba, including Las Guasimas, San Juan Hill, and the siege of Santiago. The 10th Cavalry was especially prominent at the San Juan Heights, where it helped capture Kettle Hill and advance against Spanish positions.

The term Buffalo Soldiers also applied to the 24th and 25th Infantry Regiments, but those were infantry units, not cavalry. That distinction explains why the 9th and 10th are the canonical answer to this question.