The ground which General Lee selected for a decisive trial of the strength of the two armies is near the village of Sharpsburg, between the Antietam and Potomac Rivers. It is a quiet little village at the junction of the Hagerstown turnpike, with the pike leading from Boonsboro' to Shepardstown. Hagerstown is twelve miles distant, due north; Shepardstown, three and a half miles, a little south of west, on the Potomac. In former years, it was a lively place. There were always country teams and market wagons rumbling through the town, but now the innkeepers have few travelers to eat their bacon and eggs. The villagers meet at nightfall at the hotel, smoke their pipes, drink a glass of the landlord's ale, and tell the story of the great battle. The Antietam is a rapid, crooked mill-stream. It rises north of Hagerstown, on the borders of Pennsylvania, runs toward the south, and empties into the Potomac, three miles south of Sharpsburg. Its banks are steep. In some places there are limestone ledges cropping out. At low water, it is fordable in many places, but when the clouds hang low upon the mountains and give out their showers, it roars, foams, tumbles like a cataract. Three miles northwest of the town, the Potomac makes a great bend to the east, comes within a half mile of the Hagerstown pike, then bears south toward Shepardstown. Across the Antietam, three miles from Sharpsburg, to the southeast, is the northern end of Elk Ridge,--a mountain running south to Harper's Ferry, forming the west wall of Pleasant Valley. The Antietam, below the Boonesboro' road, runs along the western base of the ridge. It is not more than four miles from the Antietam, opposite the head of the ridge, to the great bend in the Potomac, northwest of Sharpsburg. General Lee selected this narrow gate for his line of battle. It had many advantages. It was a short line. It could not be flanked. It was on commanding ground. General McClellan must attack in front. He must cross the Antietam, ascend the steep bank, over ground swept by hundreds of guns, and face a direct as well as a flanking fire. McClellan could not turn the right flank of the Rebels, because there the Antietam runs close to the base of Elk Ridge, then turns due west, and empties into the Potomac. He could not turn the left flank, for there the Rebel army leaned upon the Potomac. [Illustration: The Battle Field of Antietam. POSITIONS OF THE TWO ARMIES. The diagram represents the general positions of the divisions as they came upon the field. 1 Hooker's corps. 2 Mansfield's corps. 3 Sedgwick's division, Sumner's corps. 4 French's " " " 5 Richardson's " " " 6 Franklin's corps. 7 Porter's corps. 8 Burnside's corps. 9 McClellan's head-quarters. A Jackson. B D. H. Hill. C Longstreet. D A. P. Hill. E Lee's head-quarters. The dotted line passing through Jackson's position is a narrow farm road, along which Jackson erected his defensive works.]