Pea Ridge was the most decisive Civil War battle west of the Mississippi River. Over 26,000 soldiers struggled for two days in Northwest Arkansas in the battle that would decide the fate of Missouri.
But why was Missouri so important that so many men would risk their lives for it? Control of Missouri was the key to winning the war in the West. Military strategists, both North and South, were fully aware of this. Missouri provided an easy invasion route either north or south and controlled the Mississippi, Missouri, and Ohio Rivers. It had abundant natural resources, especially lead and iron ore, a large military-aged population and was the home of the Saint Louis Arsenal, with a stockpile of over 60,000 muskets.
In December, 1861, the situation in Missouri was deadlocked. The Missouri State Guard, the pro-secession militia army, controlled the southern & western parts of the state, while the Federal Army controlled the northern & eastern parts, as well as the railroads & waterways. The Missouri State Guard had won important victories at Carthage, Lexington, and Wilson's Creek, but had failed to force Missouri to secede from the Union.