The Lawrence Massacre (also known as Quantrill's Raid) was an attack on the town of Lawrence, Kansas on August 21, 1863. The attack was a battle in the U.S. Civil War. The Confederates won the battle. They won because groups of guerillas led by William Quantrill rode into town and shot every man they saw. They killed about 150 people.
The guerillas attacked Lawrence because the city supported abolition and because it was a center for the Jayhawkers. The Jayhawkers were free-state militia groups known for attacking plantations in the pro-slavery western counties of Missouri.