 The highway passes south of The Avalon School before it fully re-enters the city of Gaithersburg at its junction with Muddy Branch Road, east of which the highway drops to two lanes and reaches its eastern terminus at MD 117A, an unsigned connector between MD 117 and southbound MD 355 (Frederick Avenue).West Diamond Avenue continues east as a city street that parallels the Metropolitan Subdivision rail line under MD 355.West Diamond Avenue becomes Old Towne Avenue, which intersects Fulks Corner Road—which provides access to northbound MD 355—on its way to downtown Gaithersburg and the Gaithersburg MARC station.