The increasing shallowness of the river would make it almost impossible to use his best sea-going vessels. The upper forts were located on high bluffs, and it would be difficult to attack them from the river.
Admiral Farragut knew that, should he be able to pass these forts, or even to silence their guns, he could not hold them without a large land force. But he was too good a soldier to do anything in disobedience to orders.
GENERAL N.P. BANKS.
In the face of all these difficulties, he passed and repassed the forts at Vicksburg and Port Hudson. He made it plain to the Confederates that none of their batteries on the Mississippi could stop the movements of his fleet. But he found, as he had expected, that the forts could not be held until armies came to his assistance.
A large land force under General Grant besieged Vicksburg until it surrendered on July 4, 1863. Five days later, an army under General Nathaniel P. Banks succeeded in capturing Port Hudson.
These were the last Confederate strongholds on the Mississippi. Their capture gave to the Union forces the entire control of the river.
The command of the Mississippi squadron was given to David D. Porter, who had likewise been rewarded with the rank of rear admiral. He took charge of all the river boats of the fleet, while Farragut, with most of the sea-going vessels, sailed for the Atlantic coast.
ADMIRAL DAVID D. PORTER.