Bushwhacking was a form of guerrilla warfare common during the American Revolutionary War, War of 1812, American Civil War and other conflicts in which there were large areas of contested land and few governmental resources to control these tracts. This was particularly prevalent in rural areas during the Civil War where there were sharp divisions between those favoring the Union and Confederacy in the conflict. The perpetrators of the attacks were called bushwhackers. The term "bushwhacking" is still in use today to describe ambushes done with the aim of attrition.

Bushwhackers were generally part of the irregular military forces on both sides. While bushwhackers conducted well-organized raids against the military, the most dire of the attacks involved ambushes of individuals and house raids in rural areas. In the countryside, the actions were particularly inflammatory since they frequently amounted to fighting between neighbors, often to settle personal accounts. Since the attackers were without proper insignia, the Union regarded them as terrorists.