My route to the field takes me by way of the Keedysville Road. After crossing the stone bridges across the Little Antietam and then the Antietam, the road rises to the west steadily out of the stream valley.
About a mile from the last bridge and to the south lies the Susan Hoffman Farm. This is the view of the farm at about 8:15 a.m. this past Sunday. Click on the photo to enlarge.
"During the Battle of Antietam in 1862, this farm appeared much as it does now. Known as the Hoffman Hospital it provided aid for over 800 federal troops, most of whom were from Sumner's Second Corps. In a report of the Sanitary Commission, an agency similar to today's Red Cross which reviewed conditions at the field hospitals, the Hoffman Hospital was rated as excellent. Doctors Doughtery and Hayward supervised this hospital." 
A.N. Doughtery was the Medical Director of the Second Corps. Hayward was probably Surgeon Nathan Hayward, 20th Massachusetts (II Corps). He was captured in the West Woods but released.
J. Franklin Dyer, a surgeon posted to the Hoffman farm hospital kept a diary of his experiences there and on October 1 recorded this entry:
October 1, 1862
I have been for three days in charge of this hospital, where I was ordered on the day of the battle. We have been removing the wounded as fast as possible, but have yet one hundred fifty here, all of them severe cases, amputations, fractures, etc. We have seven surgeons of whom three or four each day are unfit for duty, on account of the severe labor of the past fortnight, but each one has his ward to attend, and each one is obliged to dress all the wounds in his ward, none of this being left with nurses. We would have been glad if those surgeons who visited the army soon after the battle had remained to assist us, but they did not seem willing to remain and dress stumps.
Many die of course, as the nature of their wounds is such that a large percentage of deaths is to be expected. I hope that all will soon be removed, as the atmosphere of the whole neighborhood is tainted. Some are to be removed to Frederick, but the greater number will be collected together from the field hospitals and placed in one now being prepared about a mile from here called the Smoketown hosptial. The tents are now being put up. The wounded will be much better off in tents than in houses or barns. 
 Historic American Buildings Survey, NPS, HABS No. MD-961, Martha Wagner, Historian, 1991.
 Jonah Franklin Dyer; ed. by Michael B. Chesson, The Journal of a Civil War Surgeon (Lincoln, University of Nebraska Press, 2003), p. 42.