John C. Fremont, commander of the Federal Department of the West, desired to control the Missouri river and retard Southern sympathizers in Lafayette County, Missouri. To this end, he established a garrison in Lexington in July 1861 under Colonel Charles Stifel and his 5th Regiment of the United States Reserve Corps, composed of Germans from St. Louis. Stifel and his command were soon replaced by five companies of Lafayette County Home Guards under Captain (or "Major") Frederick W. Becker. These were later supplemented by the 14th Home Guard Regiment under Lt. Col. Robert White, who assumed command. White was followed in turn by Colonel Thomas A. Marshall, who had arrived with the 1st Illinois Cavalry.
Prior to the Civil War, Lexington was an agricultural town of over 4,000 residents and county seat of Lafayette County, occupying a position of considerable local importance on the Missouri River in west-central Missouri. Hemp (used for rope production), tobacco, coal and cattle all contributed to the town's wealth, as did the river trade. Many residents were slaveowners, like those of adjacent counties; slaves comprised 31.7% of the Lafayette County population. Thus, most whites were openly pro-Confederate at the start of the conflict.
Following their victory at Wilson's Creek on August 10, the pro-Confederate Missouri State Guard, having consolidated its forces in the northern and central portions of the state, marched on Lexington under the command of Maj. Gen. Sterling Price.
On September 10, 1861, Col. James A. Mulligan arrived to take command with his 23rd Illinois Volunteer Infantry Regiment. On September 11, the 13th Missouri Infantry (USA), Van Horn's Battalion of the United States Reserve Corps, and the 27th Missouri Mounted Infantry arrived, after having evacuated Warrensburg in the face of Price's relentless advance. Mulligan now commanded 3,500 men, and quickly proceeded to construct extensive fortifications around the town's Masonic College, cutting down trees to make lines of fire and erecting earthworks around the dormitory and classroom buildings. His superiors dispatched further reinforcements under Samuel D. Sturgis, with which Mulligan hoped to hold his enlarged position, but they were ambushed by pro-Confederate forces (alerted by a secessionist telegraph tapper) and compelled to retreat.
Price and his army arrived in Lexington on September 11, 1861. However, they failed to launch an assault until two days later, by which time the Federal works proved too formidable to be easily taken.
On September 13, six companies of the 13th Missouri Infantry (USA), supported by two companies of the 1st Illinois Cavalry, battled Price's advance elements among the tombstones in Machpelah Cemetery south of town, hoping to buy time for the rest of Mulligan's men to complete their defensive preparations. Price had intended to overwhelm the Union garrison in one quick rush, but their stubborn defense of the cemetery caused his troops to exhaust much of their ammunition. This development combined with the redoubtable nature of the Union fortifications to render any further assault impractical. Price's artillery now commenced to shell the Federals.
Having bottled the Union forces up in Lexington, Price decided to await his ammunition wagons, other supplies and reinforcements before assaulting his opponent. "It is unnecessary to kill off the boys here," said he; "patience will give us what we want." Accordingly, he ordered his infantry to fall back to the county fairgrounds.
By September 18, Price had determined to order a new assault. The State Guard advanced under heavy Union artillery fire, pushing the enemy back into their inner works. Price's cannon responded to Mulligan's with nine hours of bombardment, utilizing heated shot in their endeavor to set fire to the Masonic College and other Federal positions. Mulligan stationed a youth in the attic of the college's main building, who was able to remove all incoming rounds before they could set the building ablaze.
Once described by a local newspaper as "...the largest and best arranged dwelling house west of St. Louis," the Anderson House was a three-story, Greek-Revival style house constructed by Oliver Anderson, a prominent Lexington manufacturer. Sometime around July 1861, the Anderson family was evicted from their home, which lay adjacent to Col. Mulligan's fortifications, and the Union garrison established a hospital there.
At the start of the Battle of Lexington, over a hundred sick or wounded Union soldiers occupied the Anderson House hospital. Medical care was entrusted to a surgeon named Dr. Cooley, while Father Butler, Chaplain of the 23rd Illinois, provided for the spiritual needs of the soldiers.
Because of its strategic significance, General Thomas Harris of Price's command ordered soldiers from his 2nd Division (MSG) to capture the house on September 18. Shocked at what he considered a violation of the Laws of War, Col. Mulligan ordered the structure to be retaken. Company B, 23rd Illinois, Company B, 13th Missouri, and volunteers from the 1st Illinois Cavalry charged from the Union lines and recaptured the house, suffering heavy casualties in the process. Harris’s troops recaptured the hospital later that day, and it remained in State Guard hands thereafter.
The most controversial incident of the battle would occur during the Federal assault on the Anderson house, when Union troops summarily executed three State Guard soldiers at the base of the grand staircase in the main hall. The Southerners claimed the men had already surrendered, and should have been treated as prisoners of war. The Federal troops, who had sustained numerous casualties in retaking the residence, considered the prisoners to have been in violation of the Laws of War for having attacked a hospital in the first place.
The Anderson home was heavily damaged by cannon and rifle projectiles, with many of the holes still visible both inside and outside the house (which is now a museum) today.
On September 19, the State Guard consolidated its positions, kept the Federals under heavy artillery fire, and prepared for their final attack. One problem faced by the defenders was a chronic lack of water; wells within the Union lines had gone dry, and State Guard sharpshooters were able to cover a nearby spring, picking off any man who endeavored to approach it. Surmising that a woman might succeed where his men had failed, Mulligan sent a female to the spring. Price's troops held their fire, and even permitted her to take a few canteens of water back to the beleaguered Federals. This tiny gesture, however, could not solve the ever-increasing crisis of thirst among the Union garrison, which would contribute to their ultimate undoing.
General Price had established his headquarters in Lexington in a bank building at 926 Main Street on September 18, 1861, located across the street from the Lafayette County Courthouse. During the Battle of Lexington, Price directed State Guard operations from a room on the second floor. On the following day a cannon ball, probably fired from Captain Hiram Bledsoe’s State Guard Battery, struck the courthouse only about one hundred yards from General Price’s headquarters. This projectile (which has been replaced with a croquet ball) remains lodged in the structure's far left column to this day, and has become a local tourist attraction.
On the evening of September 19, soldiers of Brig. Gen. Thomas A. Harris's 2nd Division (State Guard) began using hemp bales seized from nearby warehouses to construct a moveable breastwork facing the Union entrenchment. These bales were all soaked in river water overnight, to render them impervious to any heated rounds fired from the Federal guns. Harris's plan was for his troops to roll the bales up the hill the following day, using them for cover as they advanced close enough to the Union garrison for a final charge. The hemp bale line started in the vicinity of the Anderson house, extending north along the hillside for about 200 yards. In many places the hemp bales were stacked two high to provide additional protection.
Battle of the Hemp Bales by Dale Gallon
Early on the morning of September 20, Harris's men advanced behind his mobile breastworks. As the fighting progressed, State Guardsmen from other divisions joined Harris's men behind the hemp bales, increasing the amount of fire directed toward the Union garrison. Although the Union defenders poured red-hot cannon shot into the advancing bales, their soaking in the Missouri River the previous night had given them the desired immunity to the Federal shells. By early afternoon, the rolling fortification had advanced close enough for the Southerners to take the Union works in a final rush. Mulligan requested surrender terms after noon, and by 2:00 p.m. his men had vacated their trenches and stacked their arms.
Many years later, in his book The Rise and Fall of the Confederate Government, Southern president Jefferson Davis opined that "The expedient of the bales of hemp was a brilliant conception, not unlike that which made Tarik, the Saracen warrior, immortal, and gave his name to the northern pillar of Hercules."
Casualties were relatively low because the battle was largely fought from protective positions. Price lost only 30 men killed and 120 wounded, while the Federals lost 36 killed and 117 wounded. The relatively light casualties may be attributed to Mulligan's excellent entrenchments and Harris's hemp-bale inspiration; however, the entire Union garrison was taken prisoner.
The surrendered Union soldiers were compelled to listen to a speech by deposed pro-Confederate Missouri governor Claiborne F. Jackson, who upbraided them for entering his state without invitation and waging war upon its citizens. The Federals were then paroled by General Price, with the notable exception of Colonel Mulligan, who refused parole. Price was reportedly so impressed by the Federal commander's demeanor and conduct during and after the battle that he offered Mulligan his own horse and buggy, and ordered him safely escorted to Union lines. Mulligan was later killed at the Second Battle of Kernstown near Winchester, Virginia on July 24, 1864.
Among the casualties at the First Battle of Lexington was Lt. Col. Benjamin W. Grover, commanding the 27th Missouri Mounted Infantry, who was wounded by a musket ball in the thigh. He succumbed to his wound October 31, 1861.