Frederick County, MD

491 public highway bridges

Frederick County Bridge Snapshot

Frederick County, Maryland contains 491 public highway bridges in the FHWA National Bridge Inventory. Roughly 38.9% are rated “Good,” 40.3% “Fair,” 2.6% “Poor,” and 2.6% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in MD are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

491

Total Bridges

38.9%

Good

2.6%

Poor

2.6%

Structurally Deficient

Condition Distribution

Good

38.9% (191)

Fair

40.3% (198)

Poor

2.6% (13)

SD

2.6% (13)

All Bridges (491)

Sort:

US 340

Over: MD 180 WBR

0.3 MILE WEST OF MD 478, Frederick, MD

Built 1964 ADT: 1,183

IS 270

Over: MD 85

1.16 MILE SOUTH OF MD 355, Frederick, MD

Built 1950 ADT: 22,780

IS 270

Over: BAKER VALLEY ROAD

2.93 MILES W OF MD 80, Frederick, MD

IS 270

Over: BAKER VALLEY ROAD

2.93 MILES W OF MD 80, Frederick, MD

PARK MILLS ROAD

Over: IS 270

1.44 MILES NORTH OF MD 80, Frederick, MD

Built 1950 ADT: 80,340

IS 270 NBR

Over: MD 80

0.54 MILEWEST OF MD 355, Frederick, MD

Built 1950 ADT: 19,691

IS 270 SBR

Over: MD 80

0.54 MILEWEST OF MD 355, Frederick, MD

Built 1950 ADT: 19,691

IS 270

Over: DR. PERRY ROAD

1.15 MILES W OF MONT CO, Frederick, MD

Built 2010 ADT: 500

US 15 NBR

Over: MD 26

0.43 MILE WEST OF MD 355, Frederick, MD

Built 1957 ADT: 30,292

US 15 SBR

Over: MD 26

0.43 MILE WEST OF MD 355, Frederick, MD

Built 1968 ADT: 30,292

MOTTER AVE

Over: US 15

0.53 MI S OF MD 26, Frederick, MD

Built 1958 ADT: 76,550

US 15 NBR

Over: WEST SEVENTH ST

1.27 MILES N OF US 40, Frederick, MD

Built 1958 ADT: 14,161

US 15 SBR

Over: WEST SEVENTH ST

1.27 MILES N OF US 40, Frederick, MD

Built 1968 ADT: 14,161

US 15 NBR

Over: ROSEMONT AVE

0.77 MI N OF US 40, Frederick, MD

Built 1958 ADT: 4,090

US 15 SBR

Over: ROSEMONT AVE

0.77 MI N OF US 40, Frederick, MD

Built 1968 ADT: 4,090

US 15 NBR

Over: US 40/W. PATRICK STREET

AT US 15, Frederick, MD

Built 1958 ADT: 6,751

US 15 SBR

Over: US 40/W. PATRICK STREET

AT US 15, Frederick, MD

Built 1958 ADT: 6,751

US 15B

Over: US 15/US 40

AT US 15/US 340, Frederick, MD

Built 1955 ADT: 44,760

IS 70 EBR & RAMP L

Over: IS 270

1.35 MILES NORTH OF MD 85, Frederick, MD

Built 1955 ADT: 109,670

NEW DESIGN ROAD

Over: IS 70

0.51 MI W OF MD 355, Frederick, MD

Built 2002 ADT: 90,670

MD 355

Over: IS 70

0.83 MILE EAST OF IS 270, Frederick, MD

Built 1955 ADT: 81,630

IS 70 EBR

Over: CSX TRANS & E SOUTH ST

0.52 MI W OF MD 144FA, Frederick, MD

Built 1957 ADT: 7,841

IS 70 WBR

Over: CSX TRANS & E SOUTH ST

0.52 MI W OF MD 144 FA, Frederick, MD

Built 1957 ADT: 7,841

MD 144FA

Over: IS 70

0.53 M E OF BR NO 1010600, Frederick, MD

Built 1984 ADT: 68,623

US 15 NBR

Over: MD 77, HUNTING CREEK

0.03 M E OF MOUNTAIN ROAD, Frederick, MD

Built 1957 ADT: 8,551

NEW DESIGN ROAD

Over: IS 270

1.03 MI N OF MD 85, Frederick, MD

Built 2001 ADT: 109,670

US 340 EBR

Over: S MOUNTAIN ROAD

0.27 MI E OF MD 180, Frederick, MD

US 340 WBR

Over: S MOUNTAIN ROAD

0.27 MI E OF MD 180, Frederick, MD

MD 17

Over: US 340

1.79 MILES EAST OF MD 180, Frederick, MD

Built 1964 ADT: 26,902

CATHOLIC CHURCH RD

Over: US 340

1.57 MILES EAST OF MD 17, Frederick, MD

Built 1964 ADT: 26,902

ST MARKS ROAD

Over: US 340

2.41 MILES EAST OF MD 17, Frederick, MD

Built 1964 ADT: 26,902

MD 180

Over: US 340

3.38 MILES EAST OF MD 17, Frederick, MD

Built 1964 ADT: 28,982

HORINE ROAD

Over: US 340

0.94 M W OF LANDER ROAD, Frederick, MD

Built 1965 ADT: 28,982

LANDER ROAD

Over: US 340

0.94 M E OF HORINE ROAD, Frederick, MD

Built 1965 ADT: 32,282

US 340 EBR

Over: US 15 SBR

4.34 MILES SOUTH OF IS 70, Frederick, MD

Built 1966 ADT: 16,060

IS 270 WBR(RAMP 1)

Over: IS 70 EBR

0.09 MILE EAST OF IS 270, Frederick, MD

Built 1967 ADT: 90,670

IS 270 RAMPS J & F

Over: NEW DESIGN ROAD

0.32 M S OF BR NO 1013700, Frederick, MD

Built 2002 ADT: 15,170

MT PHILLIP ROAD

Over: IS 70

0.89 MILE EAST OF US 40AL, Frederick, MD

Built 1967 ADT: 74,920

IS 70 EBR

Over: HOLLOW ROAD

2.77 MILES W OF US 40, Frederick, MD

Built 1968 ADT: 510

IS 70 WBR

Over: HOLLOW ROAD

2.77 MILES W OF US 40, Frederick, MD

Built 1968 ADT: 510

IS 70 EBR & RAMP B

Over: MD 180

0.27 MILE EAST OF US 15, Frederick, MD

Built 1968 ADT: 25,990

IS 70 WBR

Over: MD 180

0.27 MILE EAST OF US 15, Frederick, MD

Built 1968 ADT: 25,990

IS 70 EBR

Over: HARMONY RD & LI CATOC.

1.95 MILES E OF MD 17, Frederick, MD

Built 1968 ADT: 125

IS 70 WBR

Over: HARMONY RD & LI CATOC.

1.95 MILES E OF MD 17, Frederick, MD

Built 1968 ADT: 125

IS 70 EBR

Over: US 40AL

1.37 MILES WEST OF US 40, Frederick, MD

Built 1967 ADT: 12,112

IS 70 WBR

Over: US 40AL

1.37 MILES WEST OF US 40, Frederick, MD

Built 1967 ADT: 12,112

APPALACHIAN TRAIL

Over: IS 70

0.02 M E OF WASH CO LINE, Frederick, MD

Built 1968 ADT: 58,600

IS 70 EBR

Over: MONUMENT ROAD

1.59 MILES E OF WASH CO, Frederick, MD

Built 1968 ADT: 147

IS 70 WBR

Over: MONUMENT ROAD

1.59 MILES E OF WASH CO, Frederick, MD

Built 1968 ADT: 147

IS 70 EBR

Over: MT TABOR ROAD

1.17 MILES W OF MD 17, Frederick, MD

Built 1968 ADT: 568

Read our methodology — how this data is sourced, computed, and verified.

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 5, 2026