The Sacking of Osceola was a Kansas Jayhawker attack to move pro-slavery Southerners at Osceola, Missouri on September 23, 1861. It was not approved by the Union military. The attack happened from an informal group of anti-slavery Kansas "Jayhawkers". The town of 2,077 people was plundered and burned to the ground. 200 slaves were freed and nine local citizens were court-martialed and killed. It was led by James H. Lane.