They gave us the important information that the Rebel army, thirty thousand strong, was on the Boston Mountains the day previous; and on the very day of our arrival at Huntsville, it was to begin its advance toward our front.

These men, and some others, had been sent away because they had no weapons with which to enter the fight.
Immediately on learning this, Colonel Vandever dispatched a courier to General Curtis, and prepared to set out on his return to the main army.

We marched six miles before nightfall, and at midnight, while we were endeavoring to sleep, a courier joined us from the commander-in-chief.

He brought orders for us to make our way back with all possible speed, as the Rebel army was advancing in full force.
At two o'clock we broke camp, and, with only one halt of an hour, made a forced march of forty-one miles, joining the main column at ten o'clock at night.

I doubt if there were many occasions during the war where better marching was done by infantry than on that day.
Of course, the soldiers were much fatigued, but were ready, on the following day, to take active part in the battle.
On the 5th of March, as soon as General Curtis learned of the Rebel advance, he ordered General Sigel, who was in camp at Bentonville, to fall back to Pea Ridge, on the north bank of Sugar Creek.