In a previous post I showed the ford, with 3 or 4 different names, that AP Hill used to cross the Potomac to come to Lee's aid. Hill's march was nothing short of amazing. To march that many miles and then enter a battle is a tremendous feat. Lee had no reserves left to stop Burnside and if Hill hadn't shown up it probably was all over for Lee. Without trying McClellan might have won a great victory.
This tablet is near the Hawkins Zouave monument and features an old drawing of Burnside's attack, and just how close to Sharpsburg they got.
Due to the heavy number of trees that view is no longer possible but here is the view from the tablet. A few of the buildings can be seen towards the right side of the picture.
The next two pictures actually form a panorama. The top picture is the right side and the bottom is the left. This would be the view Hill had in the area that they came upon the Harper's Ferry Road from the Millers Sawmill Road. The 12th Ohio's monument can be barely seen in the top (right) picture and a few of the monuments along Branch Avenue can also be seen.