Federal forces had to reduce these forts in connection with their general offensive down the Mississippi. (Henry- Donelson and Shiloh campaigns.)

Halleck had sent some of Pope's force in central Mo. To reinforce Grant's attack on Donelson; he also told Pope to organize a corps from the remaining troops in Mo. and to capture New Madrid.

Pope realized that the 50 heavy guns and the small fleet of gunboats the Confederates had in and near the position necessitated a regular siege operation. He sent for siege artillery and started a bombardment and the construction of approaches on 13 Mar. On this same date McCown ordered the evacuation of New Madrid and moved the garrison across the river to the peninsula in order to avoid being isolated. For this action he was relieved of command and succeeded by Mackall.

Pope now decided to cross the river south of New Madrid and turn the defense of Island No. 10. Since his supporting naval transports were upstream, he had a canal cut through the swamps so that boats could by-pass the defenses of Island No. 10. The canal was finished 4 Apr. Two Federal gunboats ran the Confederate batteries to support the river crossing, and on 7 Apr four regiments were ferried across the Mississippi to cut the Confederate line of retreat at Tiptonville. Mackall surrendered 3,500 men (over 1,500 of whom were sick) and 500 escaped through the swamps. Pope's victory opened the Mississippi to Fort Pillow, and gave him a reputation which led to his being selected by Lincoln two months later to command the Army of Virginia (2nd Bull Run Campaign).