Survey No.
Name (as assigned by HAER)
Built
Documented
Carries
Crosses
Location
County
Coordinates
MD-1
Baltimore & Ohio Railroad, Bollman Truss Bridge
1835
1984
Former Baltimore and Ohio Railroad
Little Patuxent River
Savage
Howard
39°08′05″N 76°49′31″W / 39.13472°N 76.82528°W / 39.13472; -76.82528 (Baltimore & Ohio Railroad, Bollman Truss Bridge )
MD-3
Baltimore & Ohio Railroad, Thomas Viaduct
1835
1984
CSX Capital Subdivision
Patapsco River
Elkridge
Howard
39°13′18″N 76°42′48″W / 39.22167°N 76.71333°W / 39.22167; -76.71333 (Baltimore & Ohio Railroad, Thomas Viaduct )
MD-5
Cumberland & Pennsylvania Railroad, Wills Creek Bridge (demolished)
1860
1984
Former Cumberland and Pennsylvania Railroad
Wills Creek
Cumberland
Allegany
39°40′14″N 78°47′25″W / 39.67056°N 78.79028°W / 39.67056; -78.79028 (Cumberland & Pennsylvania Railroad, Wills Creek Bridge )
MD-9
Baltimore & Ohio Railroad, Carrollton Viaduct
1829
1984
CSX Baltimore Terminal Subdivision
Gwynns Falls
Baltimore
Independent city
39°16′32″N 76°39′18″W / 39.27556°N 76.65500°W / 39.27556; -76.65500 (Baltimore & Ohio Railroad, Carrollton Viaduct )
MD-12
Baltimore & Ohio Railroad, Patterson Viaduct (replaced)
1829
1970
Former Baltimore and Ohio Railroad
Patapsco River
Ilchester
Howard
39°14′56″N 76°45′53″W / 39.24889°N 76.76472°W / 39.24889; -76.76472 (Baltimore & Ohio Railroad, Patterson Viaduct )
MD-16
Baltimore & Ohio Railroad, Harpers Ferry Bridge Piers
1836
1970
Former Baltimore and Ohio Railroad
Potomac River
Maryland Heights, Maryland , and Harpers Ferry, West Virginia
Washington County, Maryland , and Jefferson County, West Virginia
39°19′25″N 77°43′38″W / 39.32361°N 77.72722°W / 39.32361; -77.72722 (Baltimore & Ohio Railroad, Harpers Ferry Bridge Piers )
MD-22
Baltimore & Ohio Railroad, Waring Viaduct
1906
1970
CSX Metropolitan Subdivision
Great Seneca Creek
Gaithersburg
Montgomery
39°09′32″N 77°14′53″W / 39.15889°N 77.24806°W / 39.15889; -77.24806 (Baltimore & Ohio Railroad, Waring Viaduct )
MD-23
Potomac Edison Company, Chesapeake & Ohio Canal Bridge
1923
1970
Potomac Edison Company siding
Chesapeake and Ohio Canal
Williamsport
Washington
39°35′59″N 77°49′36″W / 39.59972°N 77.82667°W / 39.59972; -77.82667 (Potomac Edison Company, Chesapeake & Ohio Canal Bridge )
MD-24
Salisbury Street Bridge
1879
1970
Salisbury Street
Chesapeake and Ohio Canal
Williamsport
Washington
39°35′57″N 77°49′35″W / 39.59917°N 77.82639°W / 39.59917; -77.82639 (Salisbury Street Bridge )
MD-31
Chesapeake & Ohio Canal, Town Creek Aqueduct
1849
1974
Chesapeake and Ohio Canal
Town Creek
Oldtown
Allegany
39°31′24″N 78°32′39″W / 39.52333°N 78.54417°W / 39.52333; -78.54417 (Chesapeake & Ohio Canal, Town Creek Aqueduct )
MD-32
Chesapeake & Ohio Canal, Culvert 65
1832
1974
Chesapeake and Ohio Canal
Dickerson
Montgomery
39°11′38″N 77°28′12″W / 39.19389°N 77.47000°W / 39.19389; -77.47000 (Chesapeake & Ohio Canal, Culvert 65 )
MD-35
Poffenberger Road Bridge
1878
1983
Poffenberger Road
Catoctin Creek
Middletown
Frederick
39°22′54″N 77°34′18″W / 39.38167°N 77.57167°W / 39.38167; -77.57167 (Poffenberger Road Bridge )
MD-36
Old Mill Road Bridge
1882
1983
Old Mill Road
Owens Creek
Rocky Ridge
Frederick
39°36′07″N 77°20′19″W / 39.60194°N 77.33861°W / 39.60194; -77.33861 (Old Mill Road Bridge )
MD-37
Baltimore & Ohio Railroad, Long Bridge
1869
1983
Former Baltimore and Ohio Railroad
Antietam Creek
Keedysville
Washington
39°30′15″N 77°42′49″W / 39.50417°N 77.71361°W / 39.50417; -77.71361 (Baltimore & Ohio Railroad, Long Bridge )
MD-40
Keysville-Frederick County Road Bridge
1873
Keysville-Frederick County Road
Monocacy River
Keymar
Carroll
39°39′16″N 77°16′01″W / 39.65444°N 77.26694°W / 39.65444; -77.26694 (Keysville-Frederick County Road Bridge )
MD-41
National Road, Wilson Bridge
1819
1982
National Road
Conococheague Creek
Hagerstown
Washington
39°39′27″N 77°50′53″W / 39.65750°N 77.84806°W / 39.65750; -77.84806 (National Road, Wilson Bridge )
MD-44
Post Road Bridge
1905
1984
MD 7A
Northeast Corridor
Havre de Grace
Harford
39°32′11″N 76°06′49″W / 39.53639°N 76.11361°W / 39.53639; -76.11361 (Post Road Bridge )
MD-46
Susquehanna River Bridge
1908
1984
CSX Philadelphia Subdivision
Susquehanna River
Havre de Grace and Perryville
Harford and Cecil
39°34′08″N 76°05′13″W / 39.56889°N 76.08694°W / 39.56889; -76.08694 (Susquehanna River Bridge )
MD-52
Sharptown Bridge (replaced)
1912
1987
MD 313
Nanticoke River
Sharptown
Wicomico
38°32′45″N 75°43′10″W / 38.54583°N 75.71944°W / 38.54583; -75.71944 (Sharptown Bridge )
MD-53
Cabin John Aqueduct Bridge
1863
1987
MacArthur Boulevard and Washington Aqueduct
Cabin John Creek
Cabin John
Montgomery
38°58′22″N 77°08′53″W / 38.97278°N 77.14806°W / 38.97278; -77.14806 (Cabin John Aqueduct Bridge )
MD-68
Matthews Bridge
1914
1978
MD 146 (Dulaney Valley Road)
Loch Raven Reservoir
Baltimore
Baltimore
39°27′46″N 76°34′50″W / 39.46278°N 76.58056°W / 39.46278; -76.58056 (Matthews Bridge )
MD-69
Chesapeake & Ohio Canal, White's Ferry Iron Bridge
1865
1988
White's Ferry Road
Chesapeake and Ohio Canal
Dickerson
Montgomery
39°09′17″N 77°31′02″W / 39.15472°N 77.51722°W / 39.15472; -77.51722 (Chesapeake & Ohio Canal, White's Ferry Iron Bridge )
MD-70
Chesapeake & Ohio Canal, Iron Bridge at Lock No. 68
1910
1988
Chesapeake and Ohio Canal
Oldtown
Allegany
39°31′50″N 78°35′17″W / 39.53056°N 78.58806°W / 39.53056; -78.58806 (Chesapeake & Ohio Canal, Iron Bridge at Lock No. 68 )
MD-71
Chesapeake & Ohio Canal, McCoy's Ferry Road Culvert
1840
1988
McCoy's Ferry Road
Chesapeake and Ohio Canal
Big Spring
Washington
39°36′31″N 77°58′12″W / 39.60861°N 77.97000°W / 39.60861; -77.97000 (Chesapeake & Ohio Canal, McCoy's Ferry Road Culvert )
MD-72
Chesapeake & Ohio Canal, Prather's Neck Road Culvert
1840
1988
Chesapeake and Ohio Canal
Neck Road
Big Spring
Washington
MD-79
Mitchell's Mill Bridge (relocated)
1885
1990
Carrs Mill Road
Winter's Run
Bel Air
Harford
39°32′06″N 76°24′02″W / 39.53500°N 76.40056°W / 39.53500; -76.40056 (Mitchell's Mill Bridge )
MD-82
Stauffer Road Bridge (relocated)
1930
1996
Stauffer Road
Israel Creek
Walkersville
Frederick
39°28′01″N 77°20′45″W / 39.46694°N 77.34583°W / 39.46694; -77.34583 (Stauffer Road Bridge )
MD-83
Waverly Street Bridge
1892
1991
Waverly Street
George's Creek
Westernport
Allegany
39°29′23″N 79°02′34″W / 39.48972°N 79.04278°W / 39.48972; -79.04278 (Waverly Street Bridge )
MD-85
Governor's Bridge
1912
1992
Governor's Bridge Road
Patuxent River
Bowie
Prince George's and Anne Arundel
38°57′05″N 76°41′36″W / 38.95139°N 76.69333°W / 38.95139; -76.69333 (Governor's Bridge )
MD-88
Glendale Road Bridge (demolished)
1924
1992
Glendale Road
Deep Creek Lake
McHenry
Garrett
39°30′20″N 79°18′39″W / 39.50556°N 79.31083°W / 39.50556; -79.31083 (Glendale Road Bridge )
MD-89
Hagerstown Road Bridge (relocated)
1920
1993
Old Hagerstown Road
Little Catoctin Creek
Middletown
Frederick
39°27′13″N 77°33′36″W / 39.45361°N 77.56000°W / 39.45361; -77.56000 (Hagerstown Road Bridge )
MD-90
Crum Road Bridge
1890
1993
Crum Road
Israel Creek
Walkersville
Frederick
39°28′47″N 77°19′39″W / 39.47972°N 77.32750°W / 39.47972; -77.32750 (Crum Road Bridge )
MD-92
Carderock Overpass
1962
Carderock Access Road
Clara Barton Parkway
Carderock
Montgomery
38°58′21″N 77°11′45″W / 38.97250°N 77.19583°W / 38.97250; -77.19583 (Carderock Overpass )
MD-93
Seventy-Ninth Street Cabin John Underpass
1961
Clara Barton Parkway
79th Street
Cabin John
Montgomery
38°58′22″N 77°09′53″W / 38.97278°N 77.16472°W / 38.97278; -77.16472 (Seventy-Ninth Street Cabin John Underpass )
MD-94
Cabin John Overpass
1962
Erricson Road
Clara Barton Parkway
Cabin John
Montgomery
38°58′16″N 77°09′10″W / 38.97111°N 77.15278°W / 38.97111; -77.15278 (Cabin John Overpass )
MD-95
Cabin John Creek Bridge
1963
Clara Barton Parkway
Cabin John Creek
Cabin John
Montgomery
38°58′16″N 77°08′52″W / 38.97111°N 77.14778°W / 38.97111; -77.14778 (Cabin John Creek Bridge )
MD-96
George Washington Memorial Parkway Northbound Lane Overpass
1961
Future George Washington Memorial Parkway
Clara Barton Parkway
Glen Echo
Montgomery
38°57′46″N 77°08′09″W / 38.96278°N 77.13583°W / 38.96278; -77.13583 (George Washington Memorial Parkway Northbound Lane Overpass )
MD-97
Sycamore Island Pedestrian Overpass
1968
Trail to Sycamore Island
Clara Barton Parkway
Cabin John
Montgomery
38°57′31″N 77°07′54″W / 38.95861°N 77.13167°W / 38.95861; -77.13167 (Sycamore Island Pedestrian Overpass )
MD-98
Brookmont Pedestrian Overpass
1967
Brookmont pedestrian crossing
Clara Barton Parkway
Glen Echo
Montgomery
38°56′22″N 77°07′14″W / 38.93944°N 77.12056°W / 38.93944; -77.12056 (Brookmont Pedestrian Overpass )
MD-99
Little Falls Branch Bridge
1961
Clara Barton Parkway
Little Falls Branch
Glen Echo
Montgomery
38°56′15″N 77°07′03″W / 38.93750°N 77.11750°W / 38.93750; -77.11750 (Little Falls Branch Bridge )
MD-100-A
Suitland Parkway, Henson Creek Culvert Headwalls at Station 200 Plus 35
1944
Suitland Parkway
Henson Creek
Suitland
Prince George's
38°50′10″N 76°53′59″W / 38.83611°N 76.89972°W / 38.83611; -76.89972 (Suitland Parkway, Henson Creek Culvert Headwalls at Station 200 Plus 35 )
MD-100-B
Suitland Parkway, Henson Creek Culvert Headwalls at Station 274 Plus 50
1944
Suitland Parkway
Henson Creek
Suitland
Prince George's
38°49′51″N 76°52′30″W / 38.83083°N 76.87500°W / 38.83083; -76.87500 (Suitland Parkway, Henson Creek Culvert Headwalls at Station 274 Plus 50 )
MD-106
Wilson Mill Bridge
1930
1994
MD 161
Deer Creek
Darlington
Harford
39°37′01″N 76°12′04″W / 39.61694°N 76.20111°W / 39.61694; -76.20111 (Wilson Mill Bridge )
MD-108
Tilghman Island Bridge (relocated)
1934
1998
Chesapeake Bay Maritime Museum grounds
Perry Cabin Lane
Saint Michaels
Talbot
38°47′19″N 76°13′28″W / 38.78861°N 76.22444°W / 38.78861; -76.22444 (Tilghman Island Bridge ) \
MD-109
Proenty Road Bridge
1926
1994
Proenty Road
Jennings Run
Corriganville
Allegany
39°41′29″N 78°48′13″W / 39.69139°N 78.80361°W / 39.69139; -78.80361 (Proenty Road Bridge )
MD-110
Boston Street Bridge
1902
1994
Boston Street
Harris Creek Sewer
Baltimore
Baltimore
39°16′49″N 76°34′48″W / 39.28028°N 76.58000°W / 39.28028; -76.58000 (Boston Street Bridge )
MD-112
Weems Creek Bridge (replaced)
1929
1995
MD 436
Weems Creek
Annapolis
Anne Arundel
38°59′34″N 76°30′28″W / 38.99278°N 76.50778°W / 38.99278; -76.50778 (Weems Creek Bridge )
MD-115
Western Maryland Railway Bridge (demolished)
1932
1995
Western Maryland Railway
MD 51
Spring Gap
Allegany
39°33′52″N 78°42′48″W / 39.56444°N 78.71333°W / 39.56444; -78.71333 (Western Maryland Railway Bridge )
MD-119
River Road Bridge (replaced)
1884
1993
Casselman River Road
Casselman River
Grantsville
Garrett
39°42′07″N 79°08′12″W / 39.70194°N 79.13667°W / 39.70194; -79.13667 (River Road Bridge )
MD-120
Harmony Road Bridge (replaced)
1918
1996
Harmony Road
Little Catoctin Creek
Myersville
Frederick
39°28′56″N 77°32′06″W / 39.48222°N 77.53500°W / 39.48222; -77.53500 (Harmony Road Bridge )
MD-123
Chesapeake & Ohio Canal, Conococheague Creek Aqueduct
1834
1996
Chesapeake and Ohio Canal
Conococheague Creek
Williamsport
Washington
39°36′05″N 77°49′41″W / 39.60139°N 77.82806°W / 39.60139; -77.82806 (Chesapeake & Ohio Canal, Conococheague Creek Aqueduct )
MD-124
Allender Road Bridge (replaced)
1945
1997
Allender Road
CSX Philadelphia Subdivision
White Marsh
Baltimore
39°24′03″N 76°24′25″W / 39.40083°N 76.40694°W / 39.40083; -76.40694 (Allender Road Bridge )
MD-125
Flintville Bridge (replaced)
1927
1998
MD 623 (Flintville Road)
Broad Creek
Castleton
Harford
39°41′46″N 76°14′41″W / 39.69611°N 76.24472°W / 39.69611; -76.24472 (Flintville Bridge )
MD-127
Clarysville Bridge
1812
1994
National Road
Braddock Run
Clarysville
Allegany
39°38′35″N 78°53′21″W / 39.64306°N 78.88917°W / 39.64306; -78.88917 (Clarysville Bridge )
MD-128
Little Crossings Bridge
1813
1993
National Road
Casselman River
Grantsville
Garrett
39°41′48″N 79°08′37″W / 39.69667°N 79.14361°W / 39.69667; -79.14361 (Little Crossings Bridge )
MD-170
Bollman Truss Bridge
2007
Westminster
Carroll
MD-174
Gilpin's Falls Covered Bridge
1860
2012
Former MD 272 (North East Road)
North East Creek
North East
Cecil
39°38′56″N 75°57′20″W / 39.64889°N 75.95556°W / 39.64889; -75.95556 (Gilpin's Falls Covered Bridge )
WV-36
Baltimore & Ohio Railroad, Bollman Bridge
1868
1987
Former Baltimore and Ohio Railroad
Potomac River
Maryland Heights, Maryland , and Harpers Ferry, West Virginia
Washington County, Maryland , and Jefferson County, West Virginia
39°19′27″N 77°43′43″W / 39.32417°N 77.72861°W / 39.32417; -77.72861 (Baltimore & Ohio Railroad, Bollman Bridge )