After the Battle of Wilsonís Creek in Missouri, August 10, 1861, the command structure on both sides in Missouri underwent major overhauls. Union Major General Henry W. Halleck chose Brigadier General Samuel Ryan Curtis to command the force that fought at Wilsonís Creek, the newly christened Army of the Southwest. The Confederates also had command issues. Major General Sterling Price and Brigadier General Benjamin McCulloch feuded bitterly, and President Jefferson Davis chose Major General Earl Van Dorn to revive the Confederacy’s fortunes in the new Military District of the Trans-Mississippi.
Van Dorn’s planned to attack Curtis’s troops in northwest Arkansas and to capture St. Louis, Missouri. The Rebel Army of the West had about 16,000 men available for the upcoming struggle, while the Federal Army of the Southwest had about 10,250.
The Confederate attack began the morning of March 7, 1862. Curtis initially believed that the Rebels were trying to slip part of their force around his right flank but that most of the force was in front of him. He dispatched troops under Colonel Peter J. Osterhaus from the Second Division to determine the strength of the Confederates to the west of his army. This sparked the first shots of the battle.
The fighting on March 8 was decisive. Federals quickly silenced, destroyed, or forced their Rebel counterparts to retreat. As Curtis prepared to attack with the entire Army of the Southwest, Van Dorn realized his supply trains were still in Bentonville. Comprehending he had lost and was in danger of being trapped and destroyed, Van Dorn sent the exhausted army east toward Huntsville (Madison County). The Battle of Pea Ridge was over, and it was a resounding Union victory. The battle was one of the bloodiest, west of the Mississippi. The Confederates suffered about 2,000 casualties. The Union had 1,384 casualties.