General Grant began landing his army at Bruinsburg Mississippi on April 29th. His original plan had been to land at Grand Gulf a few miles upstream but with the timely advice of a local slave decided instead on Bruinsburg. At Grand Gulf roads both north and south were impassible due to seasonal flooding and the one road that lead eastward was impaired. This would have made it challenging to move his entire army on. Furthermore, the bulk of Bowen’s division was based there which would have meant a real fight before the chance to land enough troops to gain a bridgehead.
Note: Having a sizable slave population is an EXCELLENT way to ensure that an invading army has timely and accurate information about the disposition of your forces and up to date information of road and river conditions. This is an amazing disadvantage made worse by the fact that slave owners typically fled in the face union armies. I’m certain there must be a really good book out there on the gathering of intelligence from friendly slaves during the American Civil War.
To really isolate Vicksburg from the rest of the Confederacy, Grant needed to strike inland towards Jackson Mississippi. Jackson was not only the local thriving metropolis, and therefore a supply of both men and material, but it was the intersection of both an east-west and north-south rail line. The more Grant’s forces proved a threat to Vicksburg, the more troops would flow into Jackson from all quarters of the confederacy where, in time they would become a well supplied and numerically significant threat.
Once Mclernand’s XVII corps had crossed the Mississippi it started inland on the long march to Jackson. It had only to go a few miles before it reached Port Gibson where Brigadier’s Martin Green and Edward Tracy and and over 2400 men waited.
This part of the world is a defenders dream. It is a series of undulating ridges interspersed with creeks. Ideally the confederates would like to have occupied a position astride the road from Bruinsburg to Port Gibson, dig in and wait for the confederacy to reinforce them. Unfortunately the road connecting these to Mississippi towns inexplicably forks requiring the already intensely outnumber confederated to defend two approaches to Port Gibson.
On May 1st, General Tracy and his Alabamians assumed a position across the northern approach to Port Gibson and General Green placed his Missouri troops across the southern approach. Each were attacked multiple times throughout the day by soldiers of both Mclernand’s and McPherson’s corps . Each assault would result in either a bloody repulse or these two independent forces being pushed back and further apart.
Eventually Grant’s numbers came to dominate the battle despite the presence of some confederate reinforcements. Not only could assaults be performed in large enough numbers to succeed but virtually every position assumed by Confederates could be outflanked by Union forces. At 9:00 PM that evening confederates slipped out of their position and crossed Bayou Pierre to the north, burning bridges as the went.
The number of participants of the battle for the south can be described succinctly as “4 brigades”. This would have been around 3000 to 4000 men. Conversely Union forces would have been described as “2 corps” and would be as many men could be wedged into position in front of the Confederates. Around 40,000 to 50,000 would have been available for this task.
This battle resulted in around 800 casualties for each side. Union casualties where primarily dead and wounded while confederates suffered a large number of captured soldiers.
Abandoning Port Gibson had at least one major impact on the confederate defense of Vicksburg. The fort at Grand Gulf (a few miles north on the Mississippi) could no longer be defended and its near 5000 men (Bowen’s entire division) could no longer stay where it was. Grant would be astride their supply line (and Bowen’s line of retreat) once he rebuilt the bridges across Bayou Pierre and the fort would be quickly starved. Two options were available:
- Join the defeated troops from Port Gibson and form a new defensive line to interpose between Grant and his goal.
- Join the defenders of Vicksburg.
Ultimately the decision was taken to move the Grand Gulf defenders back to Vicksburg. While it was obvious to Grant he needed to go to Jackson, it was far less so the General Bowen and the Vicksburg Garrison. Vicksburg was the ultimate target so rushing to defend it was an easy choice. By one of those quirks of military command, the Vicksburg forces were not responsible for Jackson. Their responsibility was the banks of the Mississippi river and Vicksburg and this part of the Mississippi bank was already lost. The threat to the Vicksburg supply line that passed through Jackson was not fully appreciated at the time. Jackson nominally had its own Commander, General John Gregg, who would be on the hook to keep Jackson safe. Good luck to him.
With Confederates fleeing north towards Vicksburg, Grant’s path East to Jackson was wide open. Not only where there no troops on the roads to Jackson to slow the union advance, there was no one to warn the locals or organize the removal of supplies. There would be no scorched earth in Mississippi. Every farm and plantation held onto its equipment, animals and provisions in the vain belief that they would be spared. Grant’s army would be abundantly supplied on its drive to Jackson.
With the Road clear to Jackson, Grant pulled General Sherman’s Corps out of its position opposite Vicksburg and it began its trek through Louisiana to the crossing at Hard Times.
I know its confusing to drop city and river names at random on readers not steeped in obscure civil war history. In addition to the maps that pop up in books I use, I am very fond of a pair of maps created by Hal Jasperon that are available on Wikipedia.
Mr. Jasperon is the dean of high quality freeware maps of the civil war and the internet, and in particular Wikipedia, is literally covered in his work. His civil war maps page contains literally hundreds of strategic and battlefield maps (though sadly, not one for Champion hill).
Here is a map of Grant’s inland campaign (along with spoilers!)
Here is a map of Grant’s operation against Vicksburg prior to the invasion.