Pope, now advised of the presence of Jackson in his rear, immediately
ordered a concentration of his forces in order to crush him. McDowell’s
and Sigel’s corps, together with the division of Reynolds, were to move
to Gainesville, while Reno’s corps, with Kearny’s division of
Heintzelman’s corps, was to concentrate at Greenwich. By these
dispositions Pope hoped to intercept any reinforcements coming to
Jackson by way of Thoroughfare Gap. With Hooker’s division of
Heintzelman’s corps Pope moved along the railroad to Manassas Junction.
On the afternoon of August 27, Hooker attacked Ewell and drove him back
upon Bristoe. During the night, Ewell retired to Manassas where he
joined the rest of Jackson’s force. Pope now learned for the first time
that the whole of Jackson’s command was at Manassas. New orders were
issued for a concentration at that point. Porter was ordered to march at
1 a. m. of the 28th from Warrenton Junction and be in position at
Bristoe by daylight. McDowell, Sigel, and Reno were to move at dawn upon
Manassas Junction, while Kearny was to advance at the same hour upon
Bristoe.
About 3 a. m., August 28, Jackson began to move out of Manassas toward
Groveton. In order to mystify and mislead Pope, he sent Taliaferro along
the Manassas-Sudley Road, Ewell along the Centreville Road via
Blackburn’s Ford and the Stone Bridge to Groveton, and A. P. Hill to
Centreville and thence along the Warrenton Pike to a position near
Sudley Church.
Moving with Kearny’s division, Pope arrived at Manassas Junction at
noon, to find the town deserted. Later in the day, word was received
that the Confederates had been seen in Centreville. Pope thereupon
ordered a concentration at this place in the belief that Jackson’s whole
force was there. The corps of Heintzelman and Reno moved along the
Centreville Road; Sigel and Reynolds along the Manassas-Sudley Road;
King’s division of McDowell’s corps along the Warrenton Pike.
[Illustration: Longstreet’s troops skirmishing at Thoroughfare Gap. From
“Manassas to Appomattox.”]