Montgomery County, MD

522 public highway bridges

Montgomery County Bridge Snapshot

Montgomery County, Maryland contains 522 public highway bridges in the FHWA National Bridge Inventory. Roughly 33% are rated “Good,” 46.7% “Fair,” 4.6% “Poor,” and 4.6% 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.

522

Total Bridges

33%

Good

4.6%

Poor

4.6%

Structurally Deficient

Condition Distribution

Good

33% (172)

Fair

46.7% (244)

Poor

4.6% (24)

SD

4.6% (24)

All Bridges (522)

Sort:

IS 270 NBR

Over: MD 109 & LI BENNETT CR

0.52 MI E OF FREDERICK CO, Montgomery, MD

Built 1951 ADT: 7,232

IS 270SBR

Over: MD 109 & LI BENNETT CR

0.52 MI E OF FREDERICK CO, Montgomery, MD

Built 1951 ADT: 7,232

COMUS ROAD

Over: IS 270

1.3 MI N OF MD 121, Montgomery, MD

Built 1952 ADT: 94,940

MD 121

Over: IS 270

1.28 M N OF BR NO 1503900, Montgomery, MD

Built 1952 ADT: 94,940

IS 270

Over: WEST OLD BALTIMORE RD

1.28 MILES E OF MD 121, Montgomery, MD

Built 1954 ADT: 1,580

MD 118

Over: IS 270

0.77 M N OF BR NO 1504200, Montgomery, MD

Built 1954 ADT: 119,710

IS 270

Over: MD 124

0.49 MILE NORTH OF MD 117, Montgomery, MD

Built 1955 ADT: 29,340

IS 270

Over: MD 117

0.49 MILE NORTH OF MD 124, Montgomery, MD

Built 1954 ADT: 43,322

MUDDY BRANCH ROAD

Over: IS 270 NB C-D ROAD

0.85 MILE NORTH OF IS 370, Montgomery, MD

Built 1954 ADT: 18,879

MUDDY BRANCH ROAD

Over: IS 270

0.85 MILE NORTH OF IS 370, Montgomery, MD

Built 1954 ADT: 188,702

SHADY GROVE ROAD

Over: IS 270

0.93 MILE SOUTH OF IS 370, Montgomery, MD

Built 1987 ADT: 146,985

MD 28

Over: IS 270

0.96 MILE NORTH OF MD 189, Montgomery, MD

Built 1955 ADT: 185,579

MD 189

Over: IS 270

0.96 MILE SOUTH OF MD 28, Montgomery, MD

Built 1955 ADT: 200,505

MD 355

Over: CSX TRANS, MU 681, MU 77

0.23 MI S OF MD 124, Montgomery, MD

Built 1987 ADT: 10,182

US 29

Over: MD 650

0.16 M S OF MILESTONE DR, Montgomery, MD

Built 1957 ADT: 42,190

MD 927-MONTROSE RD

Over: IS 270 NB C-D ROAD

1.36 MILES S OF MD 189, Montgomery, MD

Built 1998 ADT: 32,573

GROSVENOR LA

Over: IS 270

0.27 MILE NORTH OF IS 695, Montgomery, MD

Built 1958 ADT: 122,760

PEDESTRIAN

Over: US 29

0.06 MI S OF SLIGO AVE, Montgomery, MD

Built 1948 ADT: 41,902

MD 187

Over: IS 270

1027 M N OF BR NO 1507700, Montgomery, MD

Built 2002 ADT: 130,450

IS 270

Over: TUCKERMAN LANE

0.25 MI W OF IS 270Y, Montgomery, MD

Built 1958 ADT: 21,000

IS 270 RAMP 'C'

Over: IS 270Y RAMPS 'B' & 'B3'

.91 M N OF DEMOCRACY BLVD, Montgomery, MD

Built 1958 ADT: 132,561

CSX TRANSPORTATION

Over: IS 270

0.23 MI S OF MD 124, Montgomery, MD

Built 1987 ADT: 152,544

DEMOCRACY BLVD

Over: IS 270Y

0.79 MILE NORTH OF IS 495, Montgomery, MD

Built 2004 ADT: 132,561

IS 495 RAMP

Over: CLARA BARTON PKWY WBR

0.55 MI W OF MD 191, Montgomery, MD

Built 1963 ADT: 21,462

IS 495

Over: MAC ARTHUR BLVD & GWMP

0.55 MI W OF MD 191, Montgomery, MD

Built 1963 ADT: 12,002

PERSIMMON TREE RD

Over: IS 495

0.06 MI S OF MD 996, Montgomery, MD

Built 1962 ADT: 214,005

IS 495

Over: IS 495X & C J CR

0.24 MILE SOUTH OF IS 495, Montgomery, MD

Built 1962 ADT: 19,820

IS 495 RAMP 'K'

Over: IS 495X NBR

0.24 MILE SOUTH OF IS 495, Montgomery, MD

Built 1964 ADT: 19,820

MD 190

Over: IS 495

1.32 MILES WEST OF MD 191, Montgomery, MD

Built 1962 ADT: 220,020

MD 191

Over: IS 495 & THOMAS BRANCH

1.32 MILES EAST OF MD 190, Montgomery, MD

Built 1962 ADT: 220,020

IS 495 OL

Over: IS 270Y

0.05 MILE NORTH OF IS 495, Montgomery, MD

Built 1996 ADT: 129,011

GREENTREE RD

Over: IS 495

.29 MILE NORTH OF IS 270Y, Montgomery, MD

Built 1962 ADT: 115,850

FERNWOOD RD

Over: IS 495

0.78 MILE SOUTH OF MD 187, Montgomery, MD

Built 1962 ADT: 115,850

IS 495

Over: MD 187 (OLD G'TOWN RD)

0.2 M N OF RYLAND DRIVE, Montgomery, MD

Built 2004 ADT: 44,540

MD 355 SBR

Over: MD 355 RAMP 1

0.10 MI N OF IS 495, Montgomery, MD

Built 1960 ADT: 10,596

MD 355 SBR

Over: IS 495 OL

1.02 MILES EAST OF MD 187, Montgomery, MD

Built 1960 ADT: 115,750

MD 355 NBR

Over: IS 495 OL

1.1 MILES EAST OF MD 187, Montgomery, MD

Built 1960 ADT: 238,050

MD 355 SBR

Over: IS 495 IL

1.02 MILES EAST OF MD 187, Montgomery, MD

Built 1960 ADT: 115,750

MD 355 NBR

Over: IS 495 IL

1.1 MILES EAST OF MD 187, Montgomery, MD

Built 1960 ADT: 238,050

IS 495

Over: MD 185(CONNECTICUT AVE)

1.24 MILE NORTH OD MD 410, Montgomery, MD

Built 1964 ADT: 44,232

IS 495

Over: KENSIGNTON PARKWAY

0.19 MI E OF MD 185, Montgomery, MD

IS 495

Over: STONEY BROOK DR, ROCK CR

0.67 MI W OF MD 391, Montgomery, MD

Built 1964 ADT: 3,140

FOREST GLEN ROAD

Over: IS 495

0.86 MILE WEST OF MD 97, Montgomery, MD

Built 1964 ADT: 239,310

CSX TRANSPORTATION

Over: IS 495

0.69 MILE WEST OF MD 97, Montgomery, MD

Built 1959 ADT: 239,310

SEMINARY ROAD

Over: IS 495

0.62 MILE WEST OF MD 97, Montgomery, MD

Built 1964 ADT: 239,310

IS 495

Over: MD 97

0.17 MILE SOUTH OF MD 192, Montgomery, MD

Built 1958 ADT: 80,840

IS 495

Over: SLIGO CREEK PARKWAY

0.61 MI E OF MD 97, Montgomery, MD

Built 1959 ADT: 5,587

US 29

Over: IS 495

0.64 MILE WEST OF MD 193, Montgomery, MD

Built 1959 ADT: 214,980

MD 193

Over: IS 495

0.64 MILE EAST OF US 29, Montgomery, MD

Built 1958 ADT: 210,927

IS 495

Over: MD 650

2.19 MILE NORTH OF MD 193, Montgomery, MD

Built 1963 ADT: 54,900

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