President Lincoln puts Henry Halleck in charge of all forces in the West. Lincoln also creates the Mountain Department, covering West Virginia and the mountainous area of Virginia. John Fremont is put in command.
Ulysses S. Grant renewed his efforts to reach Vicksburg when he tried to push gunboats past Fort Pemberton, near Greenwood. General W. W. Loring ("Old Blizzards") had built and manned the fort to prevent attacks of this nature.
4th Reconstruction Act passed by Congress. This changed the defination of majority from majority of all voters to majority of voters casting ballots in the election to approve or reject a state constitution. The bill also tried to counter the intimidation of the Ku Klux Klan.
After withdrawing from New Madrid Confederates control Island No. 10, blocking shipping on the Mississippi. Over 5,000 Confederate soldiers on the island surrender to Major General John Pope on April 8.