Between the Hagerstown pike and the Antietam the open slopes, although not always uniform, but broken, like those on the French side of the Sauerbach, by long ravines, afforded an admirable field of fire.  The lanes which cross them are sunk in many places below the surface:  in front of Sharpsburg the fields were divided by low stone walls; and these natural intrenchments added much to the strength of the position.  Nor were they the only advantages.  The belt of oaks beyond the Dunkard Church, the West Wood, was peculiarly adapted for defence.  Parallel ledges of outcropping limestone, both within the thickets and along the Hagerstown road, rising as high as a man’s waist, gave good coyer from shot and shell; the trees were of old growth, and there was little underwood.  To the north-east, however, and about five hundred yards distant across the fields, lay the East Wood, covering the slopes to the Antietam, with Poffenberger’s Wood beyond; while further to the left, the North Wood, extending across the Hagerstown pike, approached the Confederate flank.  The enemy, if he advanced to the attack in this quarter of the field, would thus find ample protection during his march and deployment; and in case of reverse he would find a rallying-point in the North and Poffenberger’s Woods, of which Hooker was already in possession.  In the space between the woods were several small farms, surrounded by orchards and stone fences; and on the slope east of the Dunkard Church stood a few cottages and barns.

Access to the position was not easy.  Only a single ford, near Snaveley’s house, exists across the Antietam, and this was commanded by the bluff on the Confederate right.  The stone bridges, however, for want of time and means to destroy them, had been left standing.  That nearest the confluence of the Antietam and the Potomac, at the Antietam Iron-works, by which A. P Hill was expected, was defended by rifle-pits and enfiladed by artillery.  The next, known as the Burnside Bridge, was completely overlooked by the heights above.  That opposite Lee’s centre could be raked throughout its length; but the fourth, at Pry’s Mill, by which Hooker and Mansfield had already crossed, was covered both from view and fire.  Roads within the position were numerous.  The Hagerstown turnpike, concealed for some distance on either side of Sharpsburg by the crest of the ridge, was admirably adapted for the movement of reserves, and another broad highway ran through Sharpsburg to the Potomac.

The position, then, in many respects, was well adapted to Lee’s purpose.  The flanks were reasonably secure.  The right rested on the Antietam.  The left was more open; but the West Wood formed a strong point d’appui, and beyond the wood a low ridge, rising above Nicodemus Run, gave room for several batteries; while the Potomac was so close that the space available for attack on this flank was much restricted.  The ground could thus be held by a comparatively small number of men, and a large