Fort Ligonier's hospitals! There are two patients' wards to the left (one behind the other) and a surgeon's hut to the right. From the sign:

The Pennsylvania Hospital is built on the original location according to contemporary maps. It was one of three flying (mobile) hospitals at Fort Ligonier in the fall of 1758. The complex consists of two patients' wards and a smaller surgeon's hut. The wards have shutters and roof ventilators for circulation of healthful air.