The Camp Jackson affair, also known as the Camp Jackson massacre, occurred during the American Civil War on May 10, 1861, when a volunteer Union Army regiment captured a unit of secessionists at Camp Jackson, outside the city of St. Louis, in the divided slave state of Missouri.

On April 23, Jackson refused to meet President Lincoln’s call for troops. Instead, he ordered the Missouri Volunteer Militia to muster all across the state. In answer to Gov. Jackson’s call, close to 1,000 men made camp in St. Louis’s Lindell Grove.

(A historical marker located in St. Louis in St. Louis, Missouri.) 1861 was a year of divided loyalties in Saint Louis. Despite a Unionist vote at a state convention, Governor Claiborne Fox Jackson favored the secession of Missouri.

The first instance of bloodshed in Missouri during the Civil War occurred in St Louis on May 10, 1861, less than a month after the war’s first shots were fired at Fort Sumter. The event in St. Louis came to be known in history as the Camp Jackson affair.

The Camp Jackson Affair, also known as the Camp Jackson Massacre, occurred on May 10, 1861, during the Civil War.

Feb 6, 2025 · Referred to either as “The Camp Jackson Affair,” or the “Camp Jackson Massacre,” the unfortunate event happened on May 10, 1861, when Brig. Gen. Nathaniel Lyon led a regiment of Federal volunteers to thwart secessionists with designs on capturing the government arsenal in St. Louis, located at Camp Jackson.

Union Captain Nathaniel Lyon leads 6,000 federal Missouri Volunteers and U.S. Regulars against the secessionist "Camp Jackson" arsenal. He then marches 669 of the captured militiamen through the streets of St. Louis, prompting a riot.

"Camp Jackson" was a bivouac area laid out in what was known as Lindell Grove, for the encampment of the Missouri Volunteer Militia who had gathered for a yearly event of muster and drill exercises in May of 1861.

The main objective of the muster was to counter the buildup of union troops in St. Louis. It was with this in mind that Camp Jackson came into being. Camp Jackson was located in a large parklike area known as Lindell's Grove, situated on what was then the western edge of the city.

St. Louis in April, 1861 was a city on edge. News of the firing on Fort Sumter, SC had reached the West. One staunch abolitionist Federal officer would force Missourians to choose allegiances through a tragic turn of events in early May, 1861.