Confederate soldiers built Fort Edward Johnson in 1862 under Brigadier General Edward Johnson to defend the Shenandoah Valley from a Union invasion from the west. A mile of trench and breastworks formed its defenses. In the early spring of 1862, the fort was garrisoned by 3,000 troops, primarily from the 12th Georgia Regiment, though most were stationed four miles east at Camp Shenandoah, where there was good drinking water and pasture for their horses. By May 1862, General John C. Fremont’s Union army, under General Robert Milroy, was moving toward the fort from the west, while “Stonewall” Jackson’s Confederate army had retreated out of the Shenandoah Valley, raising the danger that Union forces would cut off the fort from the rear. Johnson’s troops evacuated and moved toward Staunton, where they found that Jackson’s army had returned there in a lightning move that surprised both the Union generals and Jackson’s own staff. Johnson’s men then joined Jackson’s army, marched back through the fort after advance Union troops had occupied it, and continued through the mountains on the Parkersburg Turnpike to McDowell, Virginia, where the main Union army was encamped. On May 8, “Stonewall” Jackson’s army, after suffering heavy losses, sent the Union forces into full retreat and relieved the threat to Staunton.