Adam Badeau, Military history of Ulysses S. Grant from April 1861 to April 1865. Volume 1

On the 18th of September, Ord was pushed forward to within four miles of Iuka, where he found the enemy in force, on the north side of the town; and the same day, Rosecrans reported to Grant his readiness ‘to move up as close as we can to-night. . . Ord to advance from Burnsville, commence the attack and draw their attention that way, while I move in on the Jacinto and Fulton roads, massing heavily on the Fulton road, and crushing in their left, cutting off their retreat eastward. I propose to move in ten minutes for Jacinto.’ Grant ordered him to advance rapidly, and ‘let us do to-morrow all we can; it may be necessary to fall back the day following.’ The falling back was in the event of Van Dorn's attacking Corinth. This dispatch was dated fifteen minutes before seven P. M.; but, after midnight, Rosecrans sent word that he had been detained, and was still twenty miles from Iuka, and could not ‘be in,’ before one or two o'clock the next afternoon, the roads being in bad condition and the country thickly wooded. This greatly disappointed Grant, who had expected to fight on the morrow, early, and had supposed Rosecrans to be by this time far on his way to Iuka. He consequently directed Ord, who was quite ready to bring on an engagement in an hour's time, not to attack from the north until Rosecrans arrived, or until he should hear firing to the south. Rosecrans was notified, by his return messenger, of this change in Ord's instructions; but owing to the density of the forests and the difficulty of crossing the small streams and bottoms, all communication between Grant and Rosecrans was circuitous and delayed.

By half-past 4, on the afternoon of the 19th, Rosecrans, making a forced march, had arrived within