US 220 enters Maryland in southwestern Allegany County, crossing the North Branch Potomac River and its own old alignment on a bridge from Keyser to McCoole. The highway meets the eastern terminus of
MD 135 (Paxton Street) before gaining a climbing lane and ascending a hill. US 220 crosses over its old alignment again, then meets the old alignment, unsigned MD 135A, at the top of the hill. The federal highway turns northeast as McMullen Highway, a two-lane undivided road paralleling the North Branch Potomac River north to Cumberland. The highway passes through the hamlet of
Dawson, where it passes a curve of its old alignment designated
MD 830A and closely parallels
CSX's
Mountain Subdivision. US 220 splits away from the railroad tracks to follow the valley of Deep Hollow Creek between Fort Hill immediately to the east and
Dans Mountain further to the west. After passing through the hamlet of
Danville, the federal highway passes into the valley of Mill Run. After passing another curve of old alignment designated MD 830B, US 220 leaves Fort Hill and Mill Run behind. US 220 passes through the villages of
Rawlings and
Bier before intersecting the western end of
MD 956 (Patriot Parkway) near
Pinto. Beyond MD 956, US 220 enters a more densely populated area, passing through the community of
Bel Air. The federal highway enters Cresaptown, where US 220 intersects MD 53 (Winchester Road), which is also the southern terminus of
US 220 Truck. Access to northbound MD 53 is provided by
unsigned MD 636 (Warrior Drive) shortly after. After crossing Warrior Run,
Haystack Mountain flanks US 220 to the west as the federal highway passes through
Amcelle, the former site of the
Celanese chemical plant that is now the location of the
North Branch Correctional Institution. The federal highway curves through
Potomac Park, home of the
Allegany County Fairgrounds. After passing the
Upper Potomac Industrial Park, US 220 parallels CSX's Mountain Subdivision again before entering the city of Cumberland, where the highway is municipally-maintained. Shortly after, US 220 passes east of a
park and ride lot before it meets I-68 and
US 40 (National Freeway) at Exit 42. Trucks and buses are prohibited from using the ramp in the
diamond interchange from eastbound I-68 to southbound US 220; those vehicles must follow US 220 Truck instead. Greene Street, the old alignment of US 220, continues north from the interchange as a municipal street toward downtown Cumberland. US 220 becomes concurrent with eastbound I-68 and US 40 on a four-lane
freeway, passing through downtown Cumberland on a narrow, curvaceous viaduct where the highway meets the northern end of
MD 51 and the east end of
US 40 Alt. at interchanges. After passing through the eastern part of the city, US 220 exits the freeway at Exit 46 onto
MD 144 (Ali Ghan Road), which it follows east a short distance before turning north over I-68 onto a two-lane limited access highway with a speed limit of . MD 144, the old alignment of US 40, continues east toward
Rocky Gap State Park. The southbound direction of US 220 joins westbound I-68 via a long ramp on a sweeping curve. After crossing
Evitts Creek, Mason Road, and Bealls Mill Road, the federal highway reaches the intersection with
MD 807 (Bedford Road) and MD 807E (Smouses Mill Road) in
Dickens, the former being the old alignment of US 220. US 220 turns northeast, passing MD 807D (Pine Ridge Road) and MD 807C before crossing the Pennsylvania state line, where the route continues north as Bedford Valley Road toward Bedford. ==History==