On Friday, December 9, 1864, more than 11,000 troops of Union Major General Francis P. Blair, Jr.'s 17th Corps approached Pooler, Station No. 1 on the Central Railroad. Major General William T. Sherman learned that soldiers were marching in a field rather than in the road because a horse carrying an officer in the Federal 1st Alabama Cavalry Regiment had stepped on a Confederate torpedo in the road, killing the horse and blowing off the cavalryman's foot. Angered, Sherman ordered Confederate prisoners to walk in the road with picks and shovels to explode or uncover more torpedoes; ten more were found, but none exploded. Sherman and the 17th Corps camped at Pooler that day, with Savannah only nine miles away. The next morning Sherman rode forward with his staff on the Louisville road to examine Savannah's defenses and, from a railroad cut in dense woods, saw a Confederate artillery battery about 800 yards away. After Sherman stepped aside from an incoming shot, a black man crossing the track was struck in the head and killed when the cannonball ricocheted. After Major General Joseph A. Mower's division found a continuous Confederate trench line a mile to the south, Sherman concluded that a siege of Savannah was inevitable. He camped in these woods from December 10th through 15th while planning further operations, and hundreds of small mounds made by Federal soldiers to keep tents, cooking sites, and pathways above floodwater from the surrounding rice fields still remain there. During the next two days, the other three infantry corps in Sherman's army arrived: the 20th Corps reached the Savannah River on the left, the 14th Corps continued south to its right, the 17th Corps stretched from the area of the Savannah and Ogeechee Canal to west of Dean Forest Road and Salt Creek, and the 15th Corps was posted farther south to the Little Ogeechee River. Savannah was completely invested by December 12, 1864.