County profile · official public datasets

Montgomery County, MD

515 public highway bridges tracked in the FHWA National Bridge Inventory: 38.8% rated Good, 56.3% Fair, 4.9% Poor.

515
Public bridges
38.8%
Good condition
4.9%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Montgomery County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

14th
of 24 on Poor share
4.9%
Poor-condition share
515
public highway bridges
1978
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Montgomery County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Montgomery County ranks #14 of 24 Maryland counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.9%). Montgomery County, Maryland contains 515 public highway bridges. Roughly 38.8% are rated “Good,” 56.3% “Fair,” and 4.9% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

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

Total bridges

515

Public highway bridges in Montgomery County

Good condition

38.8%

200 of 515 rated 7-9

Fair condition

56.3%

290 of 515 rated 5-6

Poor condition

4.9%

25 of 515 rated 4 or below

In-state Poor-share rank

#14 of 24

Among Maryland counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 515 NBI-tracked bridges by lowest applicable component rating.

Good
38.8% (200)
Fair
56.3% (290)
Poor
4.9% (25)

Montgomery County's Poor-condition bridges carry 242,194 vehicle crossings a day

That is 1.7% of the county's reported daily bridge traffic on 4.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 9,688 crossings a day against 21,166 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 513 of 515 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

44.9% of Montgomery County's bridges have passed the 50-year mark

231 of the 515 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 38.8% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 16.5% of the county's Poor-condition bridge traffic

CLARA BARTON PARKW over CLARA BARTON PARKWAY (SB, built 1959, carries 40,057 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 25-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 242,194 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Montgomery County's bridges were built

515 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 84 of the county's bridges still in the inventory were built, which is 16.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1978, 6 years newer than the Maryland average of 1972.

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How Montgomery County compares with Maryland's closest counties by inventory size

The 5 Maryland counties nearest Montgomery County in number of bridges, with their condition splits. Its 4.9% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1974 is in line with the group.

Showing the 5 closest of 23 Maryland counties eligible for comparison.

Bridge inventory size and condition shares for Montgomery County and the 5 Maryland counties closest to it in inventory size
County Bridges Poor
Prince George's County 576 3.1%
Montgomery County (this page) 515 4.9%
Frederick County 486 2.7%
Anne Arundel County 389 1.5%
Baltimore city County 374 8.6%
Howard County 309 5.8%

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Montgomery County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Montgomery County, both outside Maryland so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MD (515 bridges here).

Similar average build year

Nearest mean year-built outside MD (1978 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 515 Good 200 Fair 290 Poor 25

All bridges (515)

HYATTSTOWN MILL RO

Fair

Over: TRIBUTARY OF LITTLE BENN

0.12 MI. E. OF JCT SR 355, Montgomery, MD

Built 2006 Load: 48.1 t ADT: 62

GROSVENOR LANE

Fair

Over: IS 270

0.27 MILE NORTH OF I-495, Montgomery, MD

Built 1958 Load: 49.0 t ADT: 4,422

CLARA BARTON PARKW

Fair

Over: RIVERSIDE DRIVE

0.7 MILES SOUTH OF I-495;, Montgomery, MD

Built 1961 Load: 49.0 t ADT: 16,120

MD 355

Fair

Over: LITTLE SENECA CREEK

1.44 MILES NORTH OF MD 27, Montgomery, MD

Built 1922 Load: 49.4 t ADT: 13,820

OAKLYN DRIVE

Fair

Over: ROCK RUN

1 MI SOUTH OF MD 189, Montgomery, MD

Built 1989 Load: 49.4 t ADT: 3,785

MD 410

Fair

Over: ROCK CREEK

0.55 MILE EAST OF MD 186, Montgomery, MD

Built 1974 Load: 49.9 t ADT: 26,931

EDMONSTON DRIVE

Fair

Over: CSXT RR & WMATA METRO

0.05 MILES EAST OF MD 355, Montgomery, MD

Built 1981 Load: 49.9 t ADT: 10,524

IS 495

Fair

Over: MD 185

1.53 MILES WEST OF MD 355, Montgomery, MD

Built 1964 Load: 50.3 t ADT: 239,310

IS 495

Fair

Over: KENSINGTON PKWY

0.19 MILE EAST OF MD 185, Montgomery, MD

Built 1964 Load: 50.8 t ADT: 239,310

IS 370 RAMP F(1)

Fair

Over: IS 270; C-D RDS & RP C/5

AT I-370, Montgomery, MD

Built 1990 Load: 50.8 t ADT: 13,596

CLUB HOLLOW ROAD

Fair

Over: BROAD RUN

0.2 MI W OF EDWARDS FERRY, Montgomery, MD

Built 1930 Load: 51.2 t ADT: 443

BLACK ROCK RD

Fair

Over: GREAT SENECA CREEK

0.7 MI N OF JCT SR 28, Montgomery, MD

Built 1965 Load: 51.2 t ADT: 373

MD 190

Fair

Over: CABIN JOHN CREEK

0.74 MILE EAST OF MD 191, Montgomery, MD

Built 1974 Load: 51.7 t ADT: 22,022

PERSIMMON TREE ROA

Fair

Over: CONGRESSIONAL CC UNDERPA

0.4 MI N OF I-495, Montgomery, MD

Built 1977 Load: 51.7 t ADT: 2,685

INDIANOLA DRIVE

Fair

Over: CSXT RR & WMATA METRO

1 MI E OF MD RTE 355, Montgomery, MD

Built 1981 Load: 52.2 t ADT: 1,075

IS 495X SB

Fair

Over: CABIN JOHN CREEK

0.02 MILE SOUTH OF GV 6, Montgomery, MD

Built 1964 Load: 53.1 t ADT: 22,160

PEACH ORCHARD ROAD

Fair

Over: PAINT BRANCH

.5 M N OF BRIGGS CHANEY R, Montgomery, MD

Built 1990 Load: 53.1 t ADT: 3,677

BRIGHTON DAM ROAD

Fair

Over: BRIGHTON DAM & TRIADELPH

1 MILE EAST OF MD 650, Montgomery, MD

Built 1944 Load: 53.1 t ADT: 7,106

MD 650

Fair

Over: SLIGO CREEK

0.43 MILE NORTH OF MD 410, Montgomery, MD

Built 1935 Load: 53.5 t ADT: 33,100

MD 185

Fair

Over: ROCK CREEK

0.13 MILE NORTH OF IS 495, Montgomery, MD

Built 1957 Load: 53.5 t ADT: 44,232

IS 270

Fair

Over: WEST OLD BALTIMORE RD

1.28 MILES S OF MD 121, Montgomery, MD

Built 1954 Load: 53.5 t ADT: 98,097

IS 495 SE RAMP

Fair

Over: CLARA BARTON PKY & CANAL

0.39 MI E OF VA LINE, Montgomery, MD

Built 1963 Load: 54.0 t ADT: 7,021

HIPSLEY MILL ROAD

Fair

Over: PATUXENT RIVER

1.8 MILES NORTH OF MD 650, Montgomery, MD

Built 1973 Load: 54.0 t ADT: 675

Briggs Chaney Road

Fair

Over: MD 200 (ICC)

0.75 MI E OF US 29, Montgomery, MD

Built 2011 Load: 54.0 t ADT: 18,193

WOOTTON PARKWAY

Fair

Over: TRIB CABIN JOHN CREEK

1.1 MILES WEST OF MD 355, Montgomery, MD

Built 1991 Load: 54.4 t ADT: 22,236

IS 495 RAMP

Fair

Over: CLARA BARTON PKWY WBR

0.55 MI W OF MD 191, Montgomery, MD

Built 1963 Load: 54.9 t ADT: 7,000

TWINBROOK PARKWAY

Fair

Over: CSXT RR & WMATA METRO

0.24 MILES EAST OF MD 355, Montgomery, MD

Built 1964 Load: 54.9 t ADT: 39,672

MD 28

Fair

Over: IS 270 & C-D ROADS

0.96 MILE NORTH OF MD 189, Montgomery, MD

Built 1955 Load: 55.3 t ADT: 26,090

CRABBS BRANCH WAY

Fair

Over: METRO ACCESS ROAD

.7 MI S OF SHADY GROVE RD, Montgomery, MD

Built 1983 Load: 56.2 t ADT: 23,523

BRIGHTON DAM ROAD

Fair

Over: REDDY BRANCH

0.9 MI E OF JCT SR 97, Montgomery, MD

Built 1910 Load: 56.7 t ADT: 743

CRABBS BRANCH WAY

Fair

Over: CRABBS CREEK

0.1 MI W OF REDLAND RD, Montgomery, MD

Built 1982 Load: 57.1 t ADT: 16,564

IS 270 & CD RDS

Fair

Over: WATTS BRANCH

0.21 MILE NORTH OF MD 28, Montgomery, MD

Built 1955 Load: 57.6 t ADT: 239,460

IS 495

Fair

Over: BRUNETT AVENUE

0.297 MILE WEST OF US 29, Montgomery, MD

Built 1959 Load: 57.6 t ADT: 232,010

IS 270 SB

Fair

Over: IS 495 OL

1.04 MILE SOUTH OF MD 187, Montgomery, MD

Built 1990 Load: 57.6 t ADT: 44,696

PURDUM ROAD

Fair

Over: BENNETT CREEK TRIBUTARY

0.6 MI N OF MOUNTAIN VIEW, Montgomery, MD

Built 1975 Load: 57.6 t ADT: 830

CATTAIL ROAD

Fair

Over: DRY SENECA CREEK

1.5 MI S OF JCT SR 28, Montgomery, MD

Built 1975 Load: 57.6 t ADT: 2,435

SUGARLAND ROAD

Fair

Over: DRY SENECA CREEK

2.3 MI S OF JCT SR 28, Montgomery, MD

Built 1971 Load: 58.0 t ADT: 433

HARRIS ROAD WEST

Fair

Over: LITTLE MONOCACY RIVER

0.7 MI S OF MT EPHRAM RD, Montgomery, MD

Built 1925 Load: 58.0 t ADT: 161

WOOTTON PARKWAY

Fair

Over: WATTS BRANCH

0.9 MI W OF JCT SR 189, Montgomery, MD

Built 1972 Load: 58.0 t ADT: 14,452

WOOTTON PARKWAY

Fair

Over: I-270

0.2 MI E SEVEN LOCKS ROAD, Montgomery, MD

Built 1990 Load: 58.0 t ADT: 19,444

MD 115

Fair

Over: NORTH BR OF ROCK CREEK

0.29 M E OF GRIST MILL DR, Montgomery, MD

Built 1917 Load: 58.5 t ADT: 16,981

MD 28 EB

Fair

Over: ROCK CREEK

0.31 M E OF AVERY ROAD, Montgomery, MD

Built 1970 Load: 58.5 t ADT: 23,866

MD 28 WB

Fair

Over: ROCK CREEK

0.31 M E OF AVERY ROAD, Montgomery, MD

Built 1970 Load: 58.5 t ADT: 24,840

GLEN ROAD

Fair

Over: PINEY BRANCH

0.6 MI W OF GLEN MILL RD, Montgomery, MD

Built 1935 Load: 59.0 t ADT: 4,689

TURKEY FOOT ROAD

Fair

Over: MUDDY BRANCH

100 FT N OF QUERY MILL RD, Montgomery, MD

Built 1968 Load: 59.0 t ADT: 1,453

EAST GUDE DRIVE (E

Fair

Over: CSXT RR & WMATA METRO

0.1 MILE EAST OF MD 355, Montgomery, MD

Built 1989 Load: 59.4 t ADT: 23,921

EDNOR ROAD

Fair

Over: NORTHWEST BRANCH

1.6 MILES WEST OF MD 650, Montgomery, MD

Built 1990 Load: 60.3 t ADT: 2,110

LONG CORNER ROAD

Fair

Over: PATUXENT RIVER

1 MILE NORTH OF GUE ROAD, Montgomery, MD

Built 1968 Load: 61.2 t ADT: 2,595

WOOTTON PARKWAY

Fair

Over: CABIN JOHN CREEK

1.1 MILES WEST MD 355, Montgomery, MD

Built 1991 Load: 61.2 t ADT: 20,825

BOWIE MILL ROAD

Fair

Over: ROCK CREEK NORTH BRANCH

1.8 MI NE OF MD 115, Montgomery, MD

Built 1959 Load: 61.7 t ADT: 10,400

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

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.