Farragut carried his fleet into the Mississippi, but found his way upstream barred by two forts on the river's bank. A great chain stretched across the river below the forts, and a fleet of river gunboats with an ironclad or two was in waiting above the forts. Chain, forts, and gunboats all gave way before Farragut's forceful will. At night he passed the forts amid a terrific cannonade. Once above them New Orleans was at his mercy. It surrendered, and with the forts was soon occupied by the Union army. The lower Mississippi was lost to the Confederacy.

General Halleck now directed the operations of the Union armies in the West. He ordered Grant to take his men up the Tennessee to Pittsburg Landing and there await the arrival of Buell with a strong force overland from Nashville. Grant encamped with his troops on the western bank of the Tennessee between Shiloh Church and Pittsburg Landing. Albert Sidney Johnston, the Confederate commander in the West, attacked him suddenly and with great fury. Soon the Union army was pushed back to the river. In his place many a leader would have withdrawn. But Grant, with amazing courage, held on. In the afternoon Buell's leading regiments reached the other side of the river. In the night they were ferried across, and Grant's outlying commands were brought to the front.