Lee had sent Longstreet to reinforce Jackson on August 13, and on the following day Lee had sent all of his remaining forces (except for two brigades) after he was certain that McClellan was leaving the Peninsula.

Lee arrives at Gordonsville to take command on August 15.

He masses the Army of Northern Virginia south of Clark's Mountain and plans a turning movement to defeat Pope before McClellan's army can arrive to reinforce it.

His plan is to send his cavalry under J.E.B. Stuart, followed by his entire army, north to the Rapidan River on August 18, screened from view by Clark's Mountain.

Stuart is to cross and destroy the railroad bridge at Somerville Ford, then move around Pope's left flank into the Federal rear, destroying supplies and blocking their possible avenues of retreat.

Logistical difficulties and cavalry movement delays will cause he plan to be abandoned.