The Battle of Wilson’s Creek on August 10, 1861, was the first major engagement of the Civil War west of the Mississippi River. It pitted a smaller but aggressive Union army against a numerically superior force of Confederate soldiers and pro-secessionist Missouri State Guard for the future of Missouri. Despite surprising the Confederates that morning, the federals withdrew by mid-day in the face of repeated Southern counterattacks. The Southern victory bolstered Confederate sentiment in Missouri and set the stage for a bold campaign in September by the Missouri State Guard against federal forces further to the north.