The Confederates knew what was coming, and when. On July 10, a beautiful 16-year-old girl named Betty Duval had arrived at Beauregard’s lines and shaken from her long, dark hair a coded dispatch from Rose Greenhow, saying that McDowell would take the offensive in mid-month. Six days later Greenhow sent another courier with a note reporting that the Union Army was on the march.
Beauregard had grandiose ideas of bringing in reinforcements from west and east to outflank McDowell, attack him from the rear, crush the Yankees and proceed to “the liberation of Maryland, and the capture of Washington.” But as McDowell’s army advanced, Beauregard faced reality. He had to defend Manassas Junction, where the Manassas Gap Railroad from the Shenandoah Valley joined the Orange & Alexandria, which connected to points south, including Richmond. He had 22,000 men, McDowell about 35,000. He would need help.
At the northern end of the Shenandoah Valley, Brig. Gen. Joseph E. Johnston commanded about 12,000 Confederates blocking Northern entry into that lush farmland and invasion route. He faced some 18,000 Federals under 69-year-old Maj. Gen. Robert Patterson, another veteran of the War of 1812. Patterson’s assignment was to prevent Johnston from threatening Washington and from moving to help Beauregard. In early July, Beauregard and Johnston, both expecting attack, were urgently seeking reinforcements from each other.
That contest ended on July 17. Beauregard informed President Davis that after skirmishing along his advance lines, he was pulling his troops back behind the little river called Bull Run, about halfway between Centreville and Manassas. That night, Davis ordered Johnston to hurry “if practicable” to aid Beauregard. Since Patterson had unaccountably pulled his Union force away down the valley, Johnston quickly issued marching orders. Screened by Col. Jeb Stuart’s cavalry, Brig. Gen. Thomas J. Jackson led his Virginia brigade out of Winchester at midday on July 18. The imminent battlefield was 57 miles away, and already the first guns had sounded along Bull Run.
Beauregard spread his brigades on a nearly ten-mile front behind the winding stream, from near Stone Bridge on the Warrenton Turnpike down to Union Mills. They concentrated at a series of fords that crossed the 40-foot-wide river. Bull Run has steep banks and is deep in spots, and would have slowed even experienced troops. The soldiers of 1861, and many of their officers, were still novices.
McDowell was 42 years old, a cautious, teetotaling officer who had served in Mexico but spent most of his career on staff duty. With green troops and his first major command, he did not want to attack the Confederates head-on. He intended to swing east and strike Beauregard’s right flank, crossing Bull Run where it was closest to the junction. But after reaching Centreville on July 18, he rode out to inspect the ground and decided against it. Before departing, he ordered Brig. Gen. Daniel Tyler, commanding his lead division, to probe the roads ahead—not to start a battle, but to make the Rebels think the army was aiming directly for Manassas. Tyler exceeded his orders: after spotting the enemy across the stream and swapping artillery rounds, he pushed his infantry at Blackburn’s Ford, testing the defenses. The Rebels, commanded there by Brig. Gen. James Longstreet, hid until the Federals were close. Then they let loose a storm of musketry that sent Tyler’s troops fleeing back toward Centreville.
In both directions, this short, sharp clash was vastly exaggerated. Back in Washington, Southern sympathizers crowding the barrooms along Pennsylvania Avenue celebrated what they already called “the Battle of Bull Run.” One Union general told the Times of London correspondent William Howard Russell that the news meant “we are whipped,” while a senator quoted General Scott as announcing “a great success.... We ought to be in Richmond by Saturday”—just two days later. Swarms of civilians rushed out from the capital in a party mood, bringing picnic baskets and champagne, expecting to cheer the boys on their way. One of the less cheerful scenes they encountered was the Fourth Pennsylvania Infantry and the Eighth New York Battery walking away on the brink of battle because their 90-day enlistments were up. For the next two days, McDowell stayed put, resupplying and planning. It was a fateful delay.
Soon after Johnston’s troops departed Winchester on July 18, he issued a communiqué to every regiment. Beauregard was being attacked by “overwhelming forces,” he wrote. “Every moment now is precious...for this march is a forced march to save the country.” Out front, Jackson’s brigade forded the Shenandoah River and toiled up the Blue Ridge through Ashby Gap before bedding down that night at the hamlet of Paris. From there it was six-plus miles downhill to the Manassas Gap Railroad station at Piedmont (now Delaplane). Arriving about 8:30 a.m., the troops jammed into freight cars, and overworked locomotives took eight more hours to bring them the last 34 miles to Manassas Junction.
The rest of Johnston’s army straggled in over the next 24 hours. Johnston himself reached Manassas about midday. To head off confusion, he asked President Davis to make clear that he was senior in rank to Beauregard. Later the two officers agreed that since Beauregard was more familiar with the immediate situation, he would retain command at the tactical level while Johnston managed the overall campaign.
That day, July 20, two opposing generals sat writing orders that, if carried through, would send their attacking armies pinwheeling around each other. Beauregard intended to strike McDowell’s left, throwing most of his army toward Centreville to cut the Federals off from Washington. McDowell prepared to cross Bull Run above Stone Bridge and come down on Beauregard’s left. His plan looked good on paper, but did not account for the arrival of Johnston’s reinforcements. Beauregard’s plan was sound in concept, but not in detail: it told which brigades would attack where, but not exactly when. He woke Johnston to endorse it at 4:30 a.m. on Sunday, July 21. By then McDowell’s army was already moving.