As the sun reached its zenith, John Pope was nearing his too. Still utterly confident that he had Jackson in his hands, Pope rode into Manassas Junction with Kearny and smugly learned that he had him on the run. His official report shows that he was no closer to the truth of the situation even after plenty of free time for reflection:
I reached Manassas Junction with Kearny’s division and Reno’s corps about 12 o’clock in the day of the 28th, less than an hour after Jackson in person had retired. I immediately pushed forward Hooker, Kearny, and Reno upon Centreville, and sent orders to Fitz John Porter to come forward to Manassas Junction. I also wrote to McDowell, and stated the facts, so far as we were then able to ascertain them, and directed him to call back the whole of his force that had come in the direction of Manassas Junction and to move forward upon Centreville.
Pope had planned to smash Jackson against Bull Run at Manassas Junction. Now he would smash him at Centreville instead.
A few miles south of Manassas Junction, Sigel’s missing corps received orders directly from Pope (which he conveniently forgot in his official report) to march straight for Centreville.
Unaware that Sigel was not only no longer on his left, but not even moving towards the same destination anymore, John Reynolds continued to lead his division up the Warrenton Turnpike [US 29] towards the old battlefield. He reported
On arriving in Gainesville the head of my column was fired upon by two pieces of the enemy in position on the heights above Groveton and to the left of the Turnpike, which were immediately replied to by Ransom’s battery, and Meade’s brigade rapidly thrown into line of battle by that general.
Reynolds was receiving fire from batteries commanded by Confederate Marylander Bushrod Johnson, of Jackson’s Division. Johnson’s brigade had been placed by Taliaferro on the steep hill above the crossroads of Groveton that morning with several pieces of artillery and the 1st Virginia Cavalry to guard against an advance from Manassas Junction. But by happy coincidence, he had captured one of McDowell’s aides, with a copy of General Order No. 10, and recognized his difficult situation immediately.
He flipped the orientation of his force from facing the Sudley Road to facing Gainesville, and moved several regiments down the Turnpike with his only two pieces of rifled artillery. It was a race with Reynolds’ vedettes.
Riding forward, I got on a high hill to the right of the road and discovered the enemy in force, their skirmishers pushing rapidly on me. I instantly brought up the rifled pieces and Forty-eighth [Virginia], and after a race beat the enemy to the hill and opened on them, driving in their cavalry and skirmishers…
John Gibbon, whose brigade was following as part of King’s division, had been sent down a country lane south of the Turnpike when the firing started and told to form up into a line of battle to prepare for an attack. Gibbon was a blunt, unpleasant, man who had brought strict discipline to his brigade when he assumed command, as well as outfitted them with distinctive black Hardee Hats. Gibbon had been raised in the south, and three of his brothers were Confederate officers, but he was staunchly loyalist. His is the classic story of the crusty regular army artillerist brought in to whip a ragtag group of misfits into order, but since they had only marched back and forth from Fredericksburg to Catlett’s station since the previous summer, it was not yet clear whether these Black Hats would become the heroes the clichéd story wanted them to be.
After a few hours of waiting on the country road, Gibbon had ridden back to McDowell and the other senior officers to get a firmer grasp on what was going on. Looking over the countryside with their field glasses, they saw heavy clouds of dust in the east, the tell-tale sign of troops moving. Gibbon recorded in his memoirs that:
I began to think that McDowell’s prediction of the night before that “something was bound to break” today was about to be verified…Still we did not move and as the day wore on our men began to get hungry. We had but few provisions along, except beef on the hoof, and some of the Regimental officers asked permission, if we were to be here long enough, to kill some of the cattle and cook the beef. I could obtain no definite information in regards to our probable stay, and after hesitating some time I gave orders to have the beef killed and cooked.
Not at all in Centreville, Jackson responded to Bushrod Johnson’s engagement of Reynolds with enthusiasm. Assuming Pope had responded to the bait of A.P. Hill’s division at Centreville, he issued orders to Taliaferro and Ewell to prepare to leave their protection on the railroad, and strike Pope’s left flank.