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

Fair-condition bridges (290)

STRINGTOWN ROAD

Fair

Over: TRIBUTARY TO LITTLE SENE

0.5 MI NE OF JCT SR 355, Montgomery, MD

Built 2017 Load: 32.7 t ADT: 7,151

WHITE GROUND ROAD

Fair

Over: TRIBUTARY OF SENECA CREE

.4 MI N OF MD 28, Montgomery, MD

Built 1925 Load: 32.7 t ADT: 615

BRIMSTONE ACADEMY

Fair

Over: TRIBUTARY TO JAMES CREEK

0.2 MI. S. OF MD 108, Montgomery, MD

Built 1988 Load: 32.7 t ADT: 539

LOGAN DRIVE

Fair

Over: ROCK RUN

1.0 MILE SOUTH OF MD-190, Montgomery, MD

Built 1972 Load: 32.7 t ADT: 1,657

BEACH DRIVE

Fair

Over: ROCK CREEK TRIBUTARY

0.81 MI N OF JCT SR 547, Montgomery, MD

Built 1965 Load: 32.7 t ADT: 8,611

LITTLE FALLS PARKW

Fair

Over: LITTLE FALLS BRANCH TRIB

0.3 MI SW OF RIVER RD, Montgomery, MD

Built 1980 Load: 32.7 t ADT: 16,691

TOWER OAKS BOULEVA

Fair

Over: CABIN JOHN CREEK

0.1 M N OF MONTROSE ROAD, Montgomery, MD

Built 1975 Load: 32.7 t ADT: 12,480

EDWARDS FERRY ROAD

Fair

Over: C&O CANAL

0.1 miles north of Potoma, Montgomery, MD

Built 1950 Load: 32.7 t ADT: 50

MD 650

Fair

Over: HAWLINGS RIVER

1.88 MILES N OF MD 108, Montgomery, MD

Built 1929 Load: 33.1 t ADT: 7,660

IS 495X

Fair

Over: CABIN JOHN CREEK

0.22 MILE NORTH OF GV 6, Montgomery, MD

Built 1964 Load: 33.1 t ADT: 19,820

BETHESDA CHURCH RO

Fair

Over: BENNETT CREEK

2.6 MILES SE OF MD 75, Montgomery, MD

Built 1990 Load: 33.6 t ADT: 4,242

MAPLE AVENUE

Fair

Over: SLIGO CREEK

0.5 MI N OF JCT SR 410, Montgomery, MD

Built 1930 Load: 33.6 t ADT: 6,024

KENSINGTON PARKWAY

Fair

Over: ROCK CREEK

0.2 MI S OF BEACH DRIVE, Montgomery, MD

Built 1910 Load: 33.7 t ADT: 3,633

MD 28

Fair

Over: LITTLE MONOCACY RIVER

1.86 MILES E OF FRED CO, Montgomery, MD

Built 1925 Load: 34.0 t ADT: 5,050

MD 355 NB

Fair

Over: IS 495 OL

0.07 MILE NORTH OF IS 495, Montgomery, MD

Built 1958 Load: 34.0 t ADT: 55,020

MD 410

Fair

Over: CSXT WMATA

0.09 MILE EAST OF US 29, Montgomery, MD

Built 1975 Load: 34.5 t ADT: 14,001

MD 182

Fair

Over: BATCHELLORS RUN

0.391 MILE SOUTH OF MD 28, Montgomery, MD

Built 1931 Load: 34.9 t ADT: 9,850

IS 495

Fair

Over: NORTHWEST BRANCH

1.00 MILE WEST OF MD 650, Montgomery, MD

Built 1967 Load: 34.9 t ADT: 222,147

WATKINS MILL ROAD

Fair

Over: CABIN BRANCH

.4 MI S OF APPLE RIDGE RD, Montgomery, MD

Built 1990 Load: 34.9 t ADT: 12,768

FOREST GLEN ROAD

Fair

Over: SLIGO CREEK

0.6 MI EAST OF MD 97, Montgomery, MD

Built 1974 Load: 34.9 t ADT: 12,150

IS 270

Fair

Over: MD 117

0.62 MILE SOUTH OF MD 124, Montgomery, MD

Built 1954 Load: 35.4 t ADT: 171,940

MD 410

Fair

Over: BRANCH OF ROCK CREEK

0.34 MILE WEST OF MD 390, Montgomery, MD

Built 1929 Load: 35.4 t ADT: 26,931

MD 547

Fair

Over: ROCK CREEK

0.66 MILE WEST OF MD 185, Montgomery, MD

Built 1932 Load: 35.4 t ADT: 10,982

SHADY GROVE ROAD

Fair

Over: IS 270 & C-D ROADS

1.02 MI S OF MD 355, Montgomery, MD

Built 1987 Load: 35.8 t ADT: 40,730

WOODFIELD SCHOOL R

Fair

Over: GREAT SENECA CREEK

0.5 MILES NORTH OF MD 124, Montgomery, MD

Built 1974 Load: 35.8 t ADT: 160

MD 355 SB

Fair

Over: MD 355 RAMP 1

0.1 MILE N OF IS 495 WBL, Montgomery, MD

Built 1959 Load: 36.3 t ADT: 55,020

FOREST GLEN ROAD

Fair

Over: IS 495

.86 W OF MD 97, Montgomery, MD

Built 1964 Load: 36.3 t ADT: 11,684

LAKE POTOMAC DRIVE

Fair

Over: WATTS BRANCH

0.1 MI N OF JCT SR 190, Montgomery, MD

Built 1985 Load: 36.7 t ADT: 139

CLARA BARTON PARKW

Fair

Over: LITTLE FALLS BRANCH

4.5 MILES SOUTH OF I-495., Montgomery, MD

Built 1961 Load: 37.2 t ADT: 16,120

PALMER ROAD SOUTH

Fair

Over: E PALMER RD STONEY CREEK

500M E OF WOOD RD, Montgomery, MD

Built 1981 Load: 37.3 t ADT: 2,750

MD 355 NB

Fair

Over: IS 495 IL & Ramp 5

1.31 MILES S OF MD 547, Montgomery, MD

Built 1960 Load: 37.6 t ADT: 55,020

NEEDWOOD ROAD

Fair

Over: ROCK CREEK

.6 MI W OF MUNCASTER MILL, Montgomery, MD

Built 1965 Load: 37.6 t ADT: 6,446

KEMP MILL ROAD

Fair

Over: TRIBUTARY TO NORTHWEST B

200 FT S OF GLENALLAN AVE, Montgomery, MD

Built 1964 Load: 37.6 t ADT: 12,820

MD 121

Fair

Over: LITTLE SENECA LAKE

0.39 MILE NORTH OF MD 117, Montgomery, MD

Built 1984 Load: 38.1 t ADT: 3,571

MD 927-MONTROSE RD

Fair

Over: IS 270 & C-D ROADS

1.36 MILES S OF MD 189, Montgomery, MD

Built 1988 Load: 38.1 t ADT: 10,211

IS 495

Fair

Over: Clara Barton Parkway EB

0.34 MILE EAST OF VA LINE, Montgomery, MD

Built 1963 Load: 38.1 t ADT: 228,218

IS 495

Fair

Over: CEDAR LANE

0.65 MILE EAST OF MD 355, Montgomery, MD

Built 1964 Load: 38.1 t ADT: 238,050

JONES MILL ROAD

Fair

Over: ROCK CREEK

0.1 MI S FORSYTHE AVENUE, Montgomery, MD

Built 1969 Load: 38.1 t ADT: 14,669

DAYTON STREET

Fair

Over: TRIBUTARY TO SLIGO CREEK

825 FEET EAST OF MD 97, Montgomery, MD

Built 1965 Load: 38.1 t ADT: 830

LITTLE FALLS PARKW

Fair

Over: WILLET BRANCH

0.1 MI N DORSET AVE, Montgomery, MD

Built 1958 Load: 38.1 t ADT: 16,840

FLOWER AVENUE

Fair

Over: SLIGO CREEK

0.28 MI SE OF MONT CO, Montgomery, MD

Built 1930 Load: 38.1 t ADT: 1,774

MD 182

Fair

Over: BUCKHORN BR

1.345 M S OF MD 28, Montgomery, MD

Built 1931 Load: 39.0 t ADT: 9,850

EAST GUDE DRIVE (W

Fair

Over: CSXT RR & WMATA METRO

0.1 MI EAST OF MD 355, Montgomery, MD

Built 1968 Load: 39.0 t ADT: 23,918

BEACH DRIVE

Fair

Over: ROCK CREEK

0.5 MI S OF JCT SR 547, Montgomery, MD

Built 1968 Load: 39.0 t ADT: 6,789

IS 270

Fair

Over: MD 124

0.62 MILE NORTH OF MD 117, Montgomery, MD

Built 1955 Load: 39.5 t ADT: 154,247

BONIFANT ROAD

Fair

Over: NORTHWEST BRANCH

0.6 MILES EAST OF MD 182, Montgomery, MD

Built 1971 Load: 39.5 t ADT: 34,277

BERRYVILLE RD

Fair

Over: SENECA CREEK TRIB

1 MI N OF JCT SR 112, Montgomery, MD

Built 1930 Load: 39.9 t ADT: 821

GREENWAY DRIVE

Fair

Over: LITTLE FALLS BRANCH

0.1 MI SOUTH OF MD 190, Montgomery, MD

Built 1962 Load: 39.9 t ADT: 886

GEORGE WASHINGTON

Fair

Over: TRIBUTARY TO NORTH BRANC

.5 MI NORTH OF MD-200, Montgomery, MD

Built 1973 Load: 39.9 t ADT: 518

BEACH DRIVE

Fair

Over: ROCK CREEK

1.3 MI SOUTH OF MD 547, Montgomery, MD

Built 1962 Load: 39.9 t ADT: 8,611

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.