The Maryland Transit Administration (MTA) operates the commuter bus service that serves several stops in the county including Myersville, Frederick, and Urbana. In 2014 what was then the #991 line was split into two lines: the #515, which originates at the downtown Frederick MARC station and the #505 originating in Hagerstown. Both lines terminate at the Shady Grove Metro Station, with some routes continuing on to the Rock Spring Business Park in Bethesda.
The 200 series Inter-County Connector (ICC) commuter bus service serves two stops in Frederick County and connects to the College Park Metro Station and a stop at the FDA in White Oak.
#515 Line – Originates at Frederick MARC station with 13 a.m. southbound trips and 14 p.m. northbound trips. Stops at Monocacy MARC station and the Urbana Park and Ride.
#505 Line – Originates in Hagerstown with 8 morning southbound trips and 9 evening northbound trips. Includes one mid-day northbound trip to the Monocacy MARC station. Southbound trips only serve the Myersville Park and Ride, while two northbound trips also serve the Urbana Park and Ride and the Monocacy MARC station.
#204 Line – 5 morning southbound trips and 6 evening northbound trips. Serves the Monocacy MARC station and the Urbana Park and Ride.