The Jonathan Hager House is a 2-story stone house with an attic that sits on a high foundation. The front, or southern façade is three bays wide with the west bay being larger than the others. The entrance is in the west bay with a single window in each of the other bays. On the second floor are all three windows directly above the first story openings. All the windows in the first and second stories have 12/12 lights and three-panel shutters. Above each window is a flat arch with stone voussoirs. A porch extends across the first story and rests on a stone foundation. Under the porch is a Dutch door with its original iron hinges. The 2-bay wide east end has a 9-light casement window centered in the gable. The second floor has a window in each bay, while the first story has one narrow window in the south bay. Beneath this window is one in the cellar with 6 lights. The north side has a window in each bay on both the first and second stories. Below the east bay is a small cellar window with vertical wood bars. The west end has an irregular window placement. There is one window in each story. The first story window is slightly to the right of center while the one in the second story is centered in the end. Centered in the gable is a 9-light casement window above which is a small, segmental arch recess. A chimney pierces the roof near the ridge between the west and center bays. The structure has a full basement, in which are two pools of water for household use, fed by clear water springs. There are some small louvered vents in the basement to circulate air around these springs.
Jonathan Hager, native of Westphalia, Germany, moved to Maryland in the 1730s and built this house c. 1740 over the 2 springs on his property. The cellar of the then 1 1/2-story house was damp, and even wet, as a result of the springs, but it protected the water sources from Indians. The loop windows, narrower on the outside of the thick cellar wall than they are on the inside, also provided protection. The Jonathan Hager House has been well-restored and retains much of its original woodwork and hardware. This is one of the earliest stone houses in Washington County. The city which grew up around Hager's house was incorporated as Hagerstown in 1814.
After a succession of owners the house was purchased by the Washington County Historical Society in 1944. The house was restored and given to the City of Hagerstown. It was opened as a house museum in 1962. It is open April - October, Friday and Saturdays, 10:00 am - 4:00 pm.