1.  The South Fork of the Shenandoah is formed by the junction of two streams, the North and South Rivers; the village of Port Republic lying on the peninsula between the two.

2.  The bridge crosses the North River just above the junction, carrying the Harrisonburg road into Port Republic; but the South River, which cuts off Port Republic from the Luray Valley, is passable only by two difficult fords.

3.  North of the village, on the left bank of the Shenandoah, a line of high bluffs, covered with scattered timber, completely commands the tract of open country which lies between the river and the Blue Ridge, and across this tract ran the road by which Shields was marching.

4.  Four miles north-west of Port Republic, near the village of Cross Keys, the road to Harrisonburg crosses Mill Creek, a strong position for defence.

By transferring his army across the Shenandoah, and burning the bridge at Port Republic, Jackson could easily have escaped Fremont, and have met Shields in the Luray Valley with superior force.  But the plain where the battle must be fought was commanded by the bluffs on the left bank of the Shenandoah; and should Fremont advance while an engagement was in progress, even though he could not cross the stream, he might assail the Confederates in flank with his numerous batteries.  In order, then, to gain time in which to deal with Shields, it was essential that Fremont should be held back, and this could only be done on the left bank.  Further, if Fremont could be held back until Shields’ force was annihilated, the former would be isolated.  If Jackson could hold the bridge at Port Republic, and also prevent Fremont reaching the bluffs, he could recross when he had done with Shields, and fight Fremont without fear of interruption.

To reverse the order, and to annihilate Fremont before falling upon Shields, was out of the question.  Whether he advanced against Fremont or whether he stood still to receive his attack, Jackson’s rear and communications, threatened by Shields, must be protected by a strong detachment.  It would be thus impossible to meet Fremont with superior or even equal numbers, and an army weaker on the battlefield could not make certain of decisive victory.

Jackson had determined to check Fremont at Mill Creek.  But the situation was still uncertain.  Fremont had halted at Harrisonburg, and it was possible that he might advance no further.  So the Confederates were divided, ready to meet either adversary; Ewell remaining at Cross Keys, and the Stonewall division encamping near Port Republic.

June 8.

On the morning of June 8, however, it was found that Fremont was moving.  Ewell’s division was already under arms.  At 8.30 A.M. his pickets, about two miles to the front, became engaged, and the Confederate regiments moved leisurely into position.