A Scholarly Monograph By Douglas Cubbison
15 May 2002
The Papers of the Blue and Gray Education Society, Number 13
The Entering Wedge
The old man gazed at the fleet a few moments in a dazed sort of way, and then as if suddenly realizing the tremendous consequences to follow threw up his hands exclaiming, My God! This is the entering wedge!
–Lieutenant Colonel Oran Perry, 69th Indiana Infantry, describing crossing of the Mississippi River at Bruinsburg April 30, 18631
After months of frustration and failure in his numerous attempts to capture the Confederate citadel of Vicksburg, Union Major General Ulysses Simpson Grant finally determined to run the fleet of Admiral David Dixon Porter past the Vicksburg batteries and to march his army south on the Louisiana bank of the Mississippi River. Once the fleet was downstream from Vicksburg, it could ferry his army across the river. Grant would then be free to maneuver into the heart of Mississippi.
While the first element of Grant’s fleet ran the Vicksburg batteries in a spectacular nighttime display on April 16, 1863, the XIII Corps under the command of Major General John Alexander McClernand and the XVII Army Corps commanded by Major General James McPherson were under orders to march down the western bank of the Mississippi River. Grant intended to link up the transports, fleet, and army at Hard Times, Louisiana.
Once the army and supporting transportation craft were in position Porter’s gunboats were to bombard Confederate fortifications at Grand Gulf. After Forts Wade and Cobun were reduced McClernand’s corps would launch an amphibious assault. Any hope of sustaining Grant’s substantial force was dependent upon Grand Gulf being under Federal control. Additionally, the position at Grand Gulf would be perfect for operations from the south against Vicksburg.
Armed with a clear understanding of their objective, Porter’s gunboats approached the Confederate fortifications at 7 A.M on April 29. Within the hour, at approximately 7:50 A.M., the first four Union gunboats Pittsburg, Carondelet, Louisville and Mound City opened fire. Although they didn’t answer for nearly a half hour, the Confederate batteries responded for the next five hours. Fort Wade was eventually silenced, but Fort Cobun was too elevated to permit effective fire from the gunboats and its fire was never effectively suppressed–indeed Fort Cobun inflicted a good deal more damage than she absorbed. With additional land batteries interspersed between the two forts and on the hills surrounding the forts, Grand Gulf was a lot more formidable than Grant initially thought. Just before 1 PM., Grant and Porter concluded that an amphibious attack would fail and called off the planned landing.
Grant had previously considered a point opposite the town of Rodney, Mississippi as an alternative should Grand Gulf prove too difficult to capture. With the assault on Grand Gulf now aborted orders were sent to both the army and navy to move to a point further downstream. Porter quietly prepared his flotilla for a night passage. Gunboats would provide covering fire. At the appointed hour the seven Federal gunboats, now headed by Benton, again pounded Fort Cobun. For a remarkably light price of just one man killed, upon the Mound City, the transports successfully completed the passage. At the same time, McClernand’s and McPherson’s corps marched four miles south to Disharoon’s Plantation. Here they boarded the transports for the crossing to Bruinsburg Landing. Once across, Grant’s intended to have his army march east to seize the suspension bridges that crossed Bayou Pierre and Little Bayou Pierre near Port Gibson. These two watercourses were serious obstacles to any movement on Vicksburg.
However, the river was not the only hindrance to Grant’s operational plan. The terrain west of Port Gibson is characterized by thick dispositions of loess or topsoil that will rapidly erode away once the vegetative cover is disturbed. The tops of the many hills in the area were cleared and in cultivation wherever the ground was level enough to be worked. The remainder of the countryside was broken by gorges and thickly covered with tall timber, underbrush, and cane indigenous to the region. Coordinated movements would be hindered by this topographical challenge.
Although he was unable to prevent the Federal passage into Mississippi, Brigadier General John Bowen, commander of the Confederate soldiers in the region, wired his superior, Confederate Lieutenant General John Clifford Pemberton that “When they cross again, they may move to Rodney.” Bowen immediately redeployed from the vicinity of Grand Gulf to a spot where he could defend both banks at the crossing points for Bayou Pierre.
Bowen first ordered Brigadier General Martin E. Green’s brigade of Arkansans and Missourians to march to Port Gibson. There they were to establish defensive positions to protect both the crossings and the advance depot of food and other supplies staged there. Perhaps in a tacit recognition of the extreme importance of Grand Gulf to Grant’s plans, Bowen remained there. This decision would have adverse ramifications for the defenders of Port Gibson on April 30th and May 1st.
In Bowen’s absence and following a survey of the terrain, Green established his primary defensive position on a ridge approximately 300 yards to the east of a small place of worship known as Magnolia Church. Green wrote that he “form[ed] [his] line on the crest of a hill running diagonally across the road, throwing out skirmishers. Green had with him the 15th and 21st regiments of Arkansas Infantry, the 12th Arkansas Sharpshooter Battalion, the 6th Mississippi Infantry Regiment, and 4 guns of the Pettus Flying Artillery.
Green positioned the 12th Arkansas Battalion astride the Rodney Road. The 15th and 21st Arkansas extended the line south in the direction of Widows Creek. The 6th Mississippi was posted to the north. The four guns of the Pettus Flying Artillery were positioned around the Foster House. Skirmishers maintained their vigil on the Magnolia Church ridge west of Green’s mainline. A combat outpost, commanded by Lieutenant William D. Tisdale of the Arkansas Sharpshooters, was located at the A. K. Shaffer House, 600 yards to the west of Green’s main position. From the Shaifer House, the Rodney Road turned east to Port Gibson, while a plantation or farm road led to the north, eventually turning east in the direction of Bayou Pierre where a barely used secondary track turned west to run through swamps in the direction of Bruinsburg.
This deployment was a critical mistake. Rather than defending Widows Creek at a potentially strong position on a prominent ridge immediately to its east, General Green chose to deploy his brigade approximately a mile further north and east on the Foster House ridge. Had Green fought at Widows Creek and been forced to retreat, the Shaffer House, Magnolia Church, and Foster House ridges all provided fine positions from which to re-establish the Confederate battle line. By leaving the Shaifer House ridge and crossroads undefended, Union forces were able to advance on Port Gibson from two fronts. Although the Foster House ridge provided a good defensive position, the Magnolia Church ridge in his front offered the Federals a sheltered position from which to launch an attack. When Green surrendered it he preordained the loss of the Foster House line. The mistake reduced Green’s options and left him but one last position (a ridge between White and Irwin’s Branches) before he would be compelled to fall back into the town. This error in judgment would compound what would soon be a very bad situation when the fighting actually took place.