Bethesda

 was a city in Maryland somewhere along the Rockville Pike. Peri Brown stayed in the Bethesda Marriott hotel twice: once for her aunt's wedding, and once when she became separated from the sixth Doctor two days before Christmas 1981. Bethesda was evidently very close to Washington, DC, as she was able to purchase a t-shirt emblazoned with that city's name in the hotel's gift shop. (PDA: Blue Box)