The battle of Pea Ridge, or Elkhorn Tavern, was the biggest battle west of the Mississippi during the American Civil War. At the end of 1861 the Confederates had been forced into the south west corner of Missouri. The main Union effort in the west in 1862 was to be along the Tennessee and Cumberland rivers. General Halleck wanted to secure his western flank before launching a major expedition, and so ordered General Samuel Curtis to clear the Confederates out of Missouri.
Curtis’s biggest problem was logistical. The Confederate forces were based at Springfield in the south west corner of Missouri. The nearest place Curtis could get to by railroad was Rolla, one hundred miles to the north east of Springfield. The two places were separated by the Ozark Plateau and barely connected even by road. Luckily for Curtis, his supply officer was Philip Sheridan, then a Captain but destined for high command. Sheridan managed to keep the 11,000 strong army supplied as it marched to Springfield and then beyond that into Arkansas.
On the Confederate side the biggest achievement was probably the creation of a potentially battle wining army. General Sterling Price had 7,000 Missourians at Springfield. General Ben McCulloch had another 8,000 troops, but he and Price loathed each other. Finally, another 1,000 Indian troops were available under Brigadier-General Albert Pike. The problem was getting the three forces to act together. Major-General Earl Van Dorn was given that job on 10 January 1862 when he was appointed to command the Trans-Mississippi department. His job was made somewhat easier by Curtis’s advance. Price was forced to retreat south, until he joined with McCulloch in northern Arkansas.
Van Dorn now had 16,000 men. Curtis had been ordered to stop just inside Arkansas. He was now outnumbered, and when Van Dorn began an advance Curtis retreated to a strong defensive position on Pea Ridge. Van Dorn had ambitious plans for an offensive that would sweep through Missouri, capture St. Louis and threaten Union operations in Kentucky.
First, he had to defeat Curtis’s army. That army was camped on the edge of high ground on the Telegraph Road, the main road across the Ozark Plateau. Van Dorn decided to outflank that position by using a road called the Bentonville Detour that cut to the north of Pea Ridge. The plan was a partial success. Price’s division completed the journey along the Bentonville Detour by ten in the morning. However, McCulloch’s division was still much further west when Curtis discovered the Confederate troops to his rear.
Reacting quickly, Curtis turned his line around to face north. One part of his force was detached to attack McCulloch, while the rest lined up against Van Dorn and Price. The ensuing Battle of Pea Ridge (7-8 March 1862) was the biggest battle west of the Mississippi.
The first day saw two almost entirely separate battles. To the west, the Confederate attack ended in disaster. McCulloch was killed, his division collapsed, and Pike, who found himself in command, was unable to rally them. Later that night the remnants of the Confederate rear straggled into Van Dorn’s camp.
The main Confederate attack, near Elkhorn Tavern, had gone better, pushing the Union forces back throughout the day. However, they had used up most of their ammunition, and Curtis had been able to hold his line.
On the second day, Curtis concentrated against the Confederate position in his rear. A well executed Union artillery bombardment slowly pushed Van Dorn back, until he was forced to abandon the field and retreat back south. Loses were fairly even. Union losses were returned at 203 dead, 980 wounded and 201 captured or missing. Confederate losses were reported at 800-1000 killed or wounded and 200-300 prisoners.
Pea Ridge protected Missouri from any serious Confederate invasion. Van Dorn and Price were soon pulled back across the Mississippi in an attempt to help defend Tennessee. Curtis meanwhile launched an attack towards Little Rock, hoping to capture the Arkansas state capitol. When it became clear that this would not be possible he made a daring decision that would be echoed later by Grant and Sherman. Cutting free from his supply lines, he marched across Arkansas, reaching the Mississippi after two weeks of living off the land, gathering supplies as he went.