for a crossing, but they did not silence the position. Grant crossed his men the next day even farther south, at Bruinsburg, Mississippi. Grant drove inland with 24,000 men, defeating an 8,000-man Confederate blocking force at Port Gibson on May 1; the batteries at Grand Gulf were abandoned the next day. Grant could either move north towards Vicksburg or head east and later turn to the west and attack Vicksburg from this direction. He chose the latter option as it provided a better chance of capturing Vicksburg's Confederate garrison and its commander, Lieutenant General John C. Pemberton. Grant put his plan in motion by having Sherman's XV Corps cross the Mississippi River at the now-abandoned Grand Gulf position and then drive towards Auburn. To Sherman's left, Major General John A. McClernand's XIII Corps covered the crossing of the Big Black River, and on the Union right was Major General John B. McPherson's XVII Corps. McPherson, who lacked experience in leading a sizable body of men in independent command, was directed to advance to Raymond via Utica. McPherson's advance was resisted by little other than militia. Union cavalrymen raided the New Orleans, Jackson and Great Northern Railroad, damaging almost of the line. On May 11, Grant ordered McPherson to take his command to Raymond and resupply there while maintaining the impression that he was targeting Jackson. Gregg's approach to Raymond Pemberton responded to the Union movements by moving his forces north along the course of the Big Black River, shadowing the Union movements but never crossing the river. Meanwhile, reinforcements were brought up from elsewhere in the Confederacy and concentrated at Jackson. General Joseph E. Johnston was ordered on May 10 to travel to Jackson to command the growing force, which would eventually amount to about 6,000 men. One of these units was the brigade of Brigadier General John Gregg, which had been sent to Jackson from Port Hudson, Louisiana. In his only aggressive action at the time, Pemberton sent Gregg a telegram ordering him to take his brigade to Raymond with hopes of intercepting a Union unit rumored to be at Utica. Both Gregg and Pemberton believed that the Union force was only a single brigade, which would have numbered about 1,500 men. In reality, the Union force at Utica was McPherson's corps, which numbered about 10,000 to 12,000 men. Expecting the main Union assault to come at the Big