I understand how the Mississippi River (and it's many tributaries) became a vital piece of infrastructure for the purposes of communications, trade, travel, and irrigation. But what about during times of war in particular?
Did the Mississippi River (or specific locations along the River) provide any additional strategic advantages for the Union or the Confederates during the Civil War?
What battles were fought on, or near the Mississippi, and how did the results affect the eventual outcome of the war? Were there navy battles on the Mississippi (perhaps using steamboats instead of seafaring vessels)?
Thanks!
The Mississippi River was EXTREMELY important to both sides during the American Civil War (ACW). It served as a natural highway of sorts to move men and materiel during the conflict, and also acted as a natural barrier that kept the Union from consolidating its gains out west pre-Vicksburg falling. When Vicksburg fell on July 4th, 1863, it effectively split the Confederacy in half, and was seen as a major blow to the Confederate war effort (even Jefferson Davis acknowledged how severe a hit this was, and he was hardly alone in that sentiment).
As far as specific battles, there were a gaggle of them. The biggest and most decisive as it concerned the river was Grant's siege and eventual capture of Vicksburg. There were also a number of ironclad engagements up and down the river, as well as Rear Adm. Farragut's expedition to take the Port of New Orleans (which kicked off the Union's efforts to take the river in earnest).
If you have questions about any specific battles, feel free to follow up with a comment. There is a lot of information online that will at least point you in the right direction if you simply google "Mississippi River Civil War." I'm not saying that you shouldn't ask follow up questions, it is just that your question as it stands now is a bit broad.
[Sources - Bruce Catton, 'Grant Moves South' & 'Glory Road'; James McPherson, 'Battle Cry of Freedom']