The siege of Lexington, also known as the First Battle of Lexington or the Battle of the Hemp Bales, was a minor conflict of the American Civil War. The siege took place from September 13 to 20, 1861 between the Union Army and the pro-Confederate Missouri State Guard in Lexington, county seat of Lafayette County, Missouri. The victory won by the Missouri Guard bolstered the considerable Southern sentiment in the area, and briefly consolidated Missouri State Guard control of the Missouri River Valley in the western part of the state.