General Halleck arrived at the landing on April 11th, established his headquarters near the river bluff, and assumed personal command. General Pope, with the Army of the Mississippi, summoned from the operations just begun before Fort Pillow, arrived on the 21st, and went into camp at Hamburg. Seasoned troops from Missouri and fresh regiments from recruiting depots arrived. The camps were pushed out farther from the river, and Halleck found 100,000 effective men under his command. The army was organized into right wing, centre, left wing, and reserve. The right wing comprised all the army of the Tennessee except the divisions of McClernand and Lewis Wallace, together with the division of General Thomas from the army of the Ohio, and was commanded by General Thomas. The remnants of the commands of Prentiss and W.H.L. Wallace were incorporated in two new divisions. The centre, composed of the Army of the Ohio, except Thomas' division, was commanded by General Buell. The left wing, the Army of the Mississippi, to which General Granger's cavalry division was still attached, was commanded by General Pope. General Pope, General Rosecrans having been assigned to him for duty, divided his command on May 29th into two wings, the right commanded by General Rosecrans, the left by General Hamilton. The reserve, under General McClernand, comprised his division and that of Lewis Wallace. General Grant was appointed second in command, without command or duty attached to that position, though he still remained commander of the District of West Tennessee. Beauregard was reinforced, almost immediately after his return, by Van Dorn with 17,000 troops seasoned by campaigns in Missouri and Arkansas, raising his effective strength to 50,000. The Confederate Government at Richmond and the State governments in the Southwest strained every resource to increase his force. Unimportant posts were denuded of their garrisons, new regiments were recruited, and Price, of Missouri, whom the Government at Richmond had refused to recognize, was appointed major-general. Beauregard found his force amount on the muster-rolls to an aggregate of more than 112,000. But sickness and absence were so prevalent that the return of effectives never quite reached 53,000. The position at Corinth was naturally strong. Standing on a long ridge in the fork of two streams, which run parallel to each other nearly to their junction, protected on the front and both flanks by swampy valleys traversed by the streams and obstructed by dense thickets, a line of earthworks running along the crest of the highland bordering the valleys, it could be approached with difficulty. The difficulty was enhanced by a belt of timber which screened the works from view. Railroads coming into the town facilitated reinforcement and supply. [Illustration: Approach to Corinth.]