June 17, 1861
Fought on June 17, 1861. the Battle of Boonville was a small, but significant engagement fought for control of central Missouri.
When the American Civil War began, sympathies in the border state of Missouri were greatly divided. Although many Missourians favored remaining in the Union, Governor Claiborne Jackson was a strong proponent of secession. Despite his secessionist leanings, Jackson declared his support for the Union and affirmed Missouri's neutrality by agreeing to terms of the Price-Harney Truce on May 12, 1861. When President Abraham Lincoln requested 75,000 troops from Missouri to take up arms against the Confederacy, Jackson withdrew his support for neutrality. A subsequent meeting between Jackson and Union Brigadier-General Nathaniel Lyon, who commanded the Department of the West, failed to resolve their differences. Instead, Lyon's Army of the West and the Missouri State Guard, commanded by former Missouri Governor Sterling Price, prepared for combat.
Following his meeting with Lyon, Governor Jackson returned to the Missouri capital at Jefferson City and evacuated the state government to Boonville on June 13, 1861. Lyon promptly dispatched an invasion force, consisting of approximately two thousand soldiers, by steamboat to Jefferson City. On June 15, he occupied the capital unopposed. The next day, Lyon left three hundred men at Jefferson City and continued his pursuit of Jackson and Price, again by steamboat. On June 17, Lyon's troops disembarked at a landing eight miles below Boonville and readied for combat.
As the Missouri State Guard prepared for the advancing Yankees, they were at a disadvantage because General Price had taken ill the day before and departed to recuperate. Governor Jackson, who had little military experience, and his nephew, Colonel John S. Marmaduke, were left in charge. Rather than face Lyon's invasion force, Marmaduke favored withdrawing to Lexington, where another militia group was assembling. For political reasons, however, Jackson opposed retreating.
After disembarking, Lyon's soldiers marched a few miles inland across the Missouri River floodplain, before encountering picket fire. The Federals quickly drove the pickets back and next encountered a line of nearly 450 militiamen along the road leading to Boonville. Lyon's troops, which included a company of regular army soldiers, smartly formed a battle line and employed their artillery to send the relatively raw and under-armed militia reeling. The battle, which was really more of a skirmish, lasted only twenty to thirty minutes. The Missouri State Guard retreated so hastily that the Federals referred to the battle as the “Boonville Races.”
After sending the Missourians fleeing, Lyon's men overran their camp, capturing supplies that the militia greatly needed. By 11 o'clock that morning, the Federal troops occupied Boonville. Meanwhile, Jackson and the Missouri State Guard retreated to the southwestern part of the state, hoping to join forces with other Southerners.
Casualty reports for the Battle of Boonville are inconsistent. Some limit militia losses to three killed and five to nine wounded, while others place total casualties around sixty, including prisoners. Union losses were approximately thirty, with five killed. No exclusively Ohio units fought in the engagement.
Though small in size, the Battle of Boonville had a significant impact on the Civil War in Missouri. Lyon's victory secured central Missouri for the Union and deprived the Confederacy use of the Missouri River during the Civil War. In addition, Lyon sent the Missouri state government into exile, preventing Jackson from exerting his influence to bring about Missouri's secession from the Union.