The sacking of Osceola was a Kansas Jayhawker initiative on September 23, 1861, to push out pro-slavery Southerners at Osceola, Missouri. It was not authorized by Union military authorities but was the work of 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 executed.