Antietam Hall is a two-story, six-bay brick dwelling, set on a low limestone foundation. The brickwork of the front or northeast elevation, and the northwest end wall are of Flemish bond. At the rear of the house, English garden wall bond is displayed, with three courses of stretchers between rows of header bricks. The projecting portion of the rear elevation displays common bonding. Across the entire front elevation is a quarter round brick watertable. Windows, with flat brick arches, and doors, are spaced evenly in the façade and appear to be grouped in pairs. All windows of the front elevation contain 9/6 pane sash, while some of the windows in the other elevations contain 6/6 or 2/2 pane sashes. Windows of the front wall are flanked with louvered shutters. The main entrance is located in the second bay from the north end of the façade wall, and is flanked by fluted pilasters and topped by a transom with rectangular panes. The door jambs are finished with quadrangular panels which match the double doors. Balancing the main entrance is a door placed in the second bay from the east end, which appears to have had a transom which has been enclosed. A one-story hip-roofed porch spans the front elevation, and is supported with chamfered square posts. Pilasters matching the main door trim are located at the ends of the front wall. A two-story porch extends along most of the rear wall, and is partially enclosed with brick. The roof is covered with slate, and terminates with a bargeboard set directly against the end walls. Eaves boxing at the front elevation is trimmed with a course of molding. Large brick chimneys with several courses of corbelling at their tops are located inside each gable end. An interior flue is located at the ridge between the second and third bays from the south end, and a smaller fourth chimney rises below the ridgeline in the southeast end. Near the house is a large barn and other outbuildings, including a 1 1/2-story four-bay brick secondary dwelling with Flemish bond at the front and a quarter round molded brick watertable extending the length of the front wall. Other elevations display common bonding. Two identical doors are present in the front elevation.
Antietam Hall is historically significant for its architecture. Although no exact construction date has been established for the house, it has several features characteristic of 18th century dwellings in Washington County. The presence of a watertable and windows with wide wooden frames showing pegged joining are indicative of early construction. The use of wrought nails and panel doors at the interior as well as the method of construction employed in the first story flooring all suggest an 18th century building date. The structure is also significant for the original decorative stenciling which is present in several rooms on the second story. The presence of such early stenciling is particularly outstanding and certainly rare in Washington County. Few, if any, other examples are in existence in the area.
The front porch noted in the Nomination has been removed. The house and other buildings are well maintained and are in excellent condition.