The Battle of Pea Ridge was one of the more significant battles of the Civil War in the United States. It occurred on the 7th of March, 1862, in northwest Arkansas, and marked the real beginning of the western theatre of the Civil War.
In December of 1861, General Samuel R. Curtis took command of the Union Army of the Southwest (the Union being the North, or the remaining parts of the United States) with instructions to drive the Confederate (i.e., the South, or the rebelling states) army out of the state of Missouri. Several skirmishes in late 1861 and early 1862 resulted in the Confederate army, led by Major General Sterling Price, being pushed back to the Boston Mountains in northwest Arkansas by the beginning of February.
As March 1862 dawned, the Confederacy sent reinforcements to General Price, led by General Benjamin McCulloch and the commander of Confederate forces in Arkansas, Earl van Dorn. The combined force dubbed themselves the Army of the West and numbered around 17,000. The group planned to re-invade Missouri, take St. Louis, and then march across Illinois to Chicago, taking northern general Ulysses S. Grant by surprise. Van Dorn planned to start this offensive by defeating Curtis's army, which numbered only 11,000, which would open largely undefended Missouri all the way to St. Louis.
Van Dorn's plan was to split his forces in half, letting Sterling Price lead one half around the Union's right flank and attack them from the rear, while McCulloch would attack from the front, sandwiching the smaller Union army. The only problem was that McCulloch arrived very late to the battle, and his tardiness made all of the difference.
As soon as Curtis heard that the Confederates were attacking from the north on the morning of March 7th, he turned his forces around to face north and met Price's flank head on. As the battle began to grow in strength near Elkhorn Tavern, Arkansas, Curtis noticed a high plateau to the west of the town, which he ordered his men to march up. The plateau was called, of course, Pea Ridge. The Union Army, led by Curtis, fortified themselves on top of this ridge and began to rout the flank led by Price.
When McCulloch began charging into town in the early afternoon, Curtis ordered a small band of skirmishers to descend the plateau and head south to slow him down and buy them some time, as the Union army was decimating Price's flank. The skirmishers headed straight for McCulloch's flank, took out McCulloch himself, as well as his second-in-command. McCulloch's flank fell into disarray, and Price's flank to the north of the Union army was soundly defeated as well.
As a result of this rousing defeat, Van Dorn assembled the remaining troops from both flanks in the town of Elkhorn Tavern that evening. Noticing the movement, Curtis divided his troops into four flanks and conquered the town, two from each side. Greatly outnumbered, the Confederates were routed once again.
This battle pretty much sealed the Confederacy's fate in the western theatre. They never again mounted a serious charge into Missouri and were gradually pressed southward into Louisiana and Mississippi as the war wore on. This decisive battle, which was won decisively by an undermanned Union army, marked the beginning of the end for the Confederacy in the west.
This battle is re-enacted annually in several places. Perhaps the most notable re-enactment is the one held each September in Keokuk, Iowa, which is elaborately staged with full costumery. It is well worth seeing if you are in the area in the early fall, as the city puts on a nice festival around the re-enactment.