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

Good-condition bridges (200)

MD 119

Good

Over: GREAT SENECA CREEK

2.0 MILES NORTH OF MD 124, Montgomery, MD

Built 1989 Load: 22.2 t ADT: 10,766

IS 370 & RAMP 9

Good

Over: CSX/MARC

0.56 MILE EAST OF MD 355, Montgomery, MD

Built 1989 Load: 25.4 t ADT: 78,741

SEMINARY ROAD

Good

Over: IS 495

0.10 MI E OF MD 192, Montgomery, MD

Built 1964 Load: 25.9 t ADT: 9,275

MD 119

Good

Over: GREAT SENECA CREEK

2.0 MILES NORTH OF MD 124, Montgomery, MD

Built 1989 Load: 30.4 t ADT: 10,344

MD 28

Good

Over: BR OF WATTS BRANCH

0.53 MILE WEST OF IS 270, Montgomery, MD

Built 1988 Load: 32.7 t ADT: 47,601

MD 190

Good

Over: LITTLE FALLS

0.44 MI W OF WASH DC, Montgomery, MD

Built 1962 Load: 32.7 t ADT: 22,152

IS 495

Good

Over: SLIGO CREEK TRAIL

0.507 M E OF BR NO 15130, Montgomery, MD

Built 2002 Load: 32.7 t ADT: 232,010

POTOMAC CREST DRIV

Good

Over: SNAKEDEN BRANCH

1 MILE WEST OF I-270, Montgomery, MD

Built 1995 Load: 32.7 t ADT: 513

GAME PRESERVE ROAD

Good

Over: WHETSTONE RUN

0.2 MI NORTH OF MD 355, Montgomery, MD

Built 1990 Load: 33.1 t ADT: 1,982

MD 355

Good

Over: LITTLE BENNETT CREEK

0.10 MILE SOUTH OF MD 109, Montgomery, MD

Built 1925 Load: 34.0 t ADT: 7,540

JERUSALEM ROAD

Good

Over: DRY SENECA CREEK

0.37 MILES EAST OF MD 109, Montgomery, MD

Built 2013 Load: 34.0 t ADT: 1,050

MD 200 (ICC)

Good

Over: ROCK CREEK

3.30 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 34.0 t ADT: 62,479

MD 119

Good

Over: MUDDY BRANCH

0.9 MI SE OF JCT SR 124, Montgomery, MD

Built 1988 Load: 34.5 t ADT: 34,401

MD 119

Good

Over: SHADY BRANCH

0.13 M N OF SAM EIG HWY, Montgomery, MD

Built 1988 Load: 34.5 t ADT: 39,581

MD 195

Good

Over: SLIGO CR PKWY & SLIGO CR

0.5 MILE NORTH OF MD 410, Montgomery, MD

Built 1932 Load: 35.4 t ADT: 7,500

MD 119

Good

Over: LONG DRAUGHT BRANCH

1.66 MILE NORTH OF MD 124, Montgomery, MD

Built 1990 Load: 35.4 t ADT: 10,344

Old Columbia Pike

Good

Over: MD-200 & Ramps SW & EN

0.18 Mi. West of US 29, Montgomery, MD

Built 2011 Load: 35.8 t ADT: 9,633

CEDAR LANE

Good

Over: ROCK CREEK

AT BEACH DRIVE, Montgomery, MD

Built 1959 Load: 36.0 t ADT: 13,424

MONTEVIDEO ROAD

Good

Over: DRY SENECA CREEK

1.1 M N OF RIVER RD, Montgomery, MD

Built 1910 Load: 36.3 t ADT: 150

SUMMIT AVENUE

Good

Over: CSXT RAILROAD

0.14 MILE NORTH OF MD 547, Montgomery, MD

Built 1996 Load: 37.6 t ADT: 9,746

WASHINGTONIAN BLVD

Good

Over: SAM EIG HIGHWAY

0.5 MI WEST OF I-270, Montgomery, MD

Built 1998 Load: 37.6 t ADT: 9,998

MD 200 (ICC) EB

Good

Over: NORTH BRANCH ROCK CREEK

1.51 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 37.6 t ADT: 31,652

IS 495

Good

Over: MD 97

0.62 M E OF SEMINARY ROAD, Montgomery, MD

Built 1960 Load: 38.1 t ADT: 232,010

MD 200 (ICC) EB

Good

Over: US 29 & Ramp SE NB&EB

0.7 mi W of Briggs Chaney, Montgomery, MD

Built 2011 Load: 38.1 t ADT: 21,522

KINSTER DRIVE

Good

Over: LITTLE SENECA CREEK TRIB

0.1 MI N OF CRYSTAL ROCK, Montgomery, MD

Built 2018 Load: 38.2 t ADT: 144

MD 200 (ICC) EB

Good

Over: TRIBUTARY OF NBRC

1.34 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 39.5 t ADT: 31,652

MD 200 (ICC) WB

Good

Over: Paint Branch

1.40 Mi East of MD650, Montgomery, MD

Built 2010 Load: 39.5 t ADT: 32,064

MD 200 (ICC) WB

Good

Over: US 29 & Ramp SE NB&EB

0.5 Mi S of Briggs Chaney, Montgomery, MD

Built 2011 Load: 39.5 t ADT: 21,574

MD 119

Good

Over: GUNNERS BR CSXT RR

.5 MI S OF MIDDLEBROOK RD, Montgomery, MD

Built 1987 Load: 39.9 t ADT: 7,535

New Hampshire Ave

Good

Over: MD 200 (ICC)

5.03 Mi East of MD97, Montgomery, MD

Built 2010 Load: 39.9 t ADT: 31,575

MD 200 (ICC) WB

Good

Over: Shady Grove Road

4.86 MI W. OF MD 97, Montgomery, MD

Built 2010 Load: 40.4 t ADT: 30,827

MD 193

Good

Over: IS 495

0.59 MILE EAST OF US 29, Montgomery, MD

Built 1958 Load: 40.5 t ADT: 44,000

IS 270 RAMP

Good

Over: UNNAMED TRIB TO SENECA C

1.0 Mile North of MD 124, Montgomery, MD

Built 2020 Load: 40.5 t

MD 118

Good

Over: IS 270

0.33 M N OF AIRCRAFR DR, Montgomery, MD

Built 1954 Load: 40.8 t ADT: 28,651

MD 28

Good

Over: BUCKHORN RUN

AT INTERSECTION OF MD 182, Montgomery, MD

Built 2001 Load: 40.8 t ADT: 21,671

MD 390

Good

Over: CSX TRANSPORTATION

0.45 MI N OF MD 410, Montgomery, MD

Built 1958 Load: 41.3 t ADT: 35,062

SHADY GROVE ROAD

Good

Over: IS 370

2.43 MI. E. OF I-270, Montgomery, MD

Built 1989 Load: 41.3 t ADT: 53,010

WHITES FERRY ROAD

Good

Over: BROAD RUN TRIBUTARY

0.3 MI E OF WASCHE ROAD, Montgomery, MD

Built 2014 Load: 41.3 t ADT: 1,907

MD 200 (ICC) EB

Good

Over: Gum Springs & Paint Bran

1.40 Mi East of MD650, Montgomery, MD

Built 2010 Load: 41.3 t ADT: 31,755

Watkins Mill Road

Good

Over: IS 270 (Wash. Natl Pike

0.75 MI. N of MD 124, Montgomery, MD

Built 2020 Load: 41.5 t

MD 97

Good

Over: Reddy Branch

2 MI. NORTH OF OLNEY, Montgomery, MD

Built 2022 Load: 41.5 t ADT: 10,400

PINEY MEETINGHOUSE

Good

Over: WATTS BRANCH

0.8 MILES NORTH OF MD 190, Montgomery, MD

Built 2017 Load: 41.5 t ADT: 6,724

I-370 RAMP - B

Good

Over: CRABBS BRANCH WAY

0.56 MI E OF MD 355, Montgomery, MD

Built 2009 Load: 41.7 t ADT: 3,953

MD 200 (ICC) WB

Good

Over: TRIBUTARY OF NBRC

1.34 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 41.7 t ADT: 30,827

EMORY LANE

Good

Over: MD 200 (ICC)

0.93 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 41.7 t ADT: 8,133

ELMHIRST PARKWAY

Good

Over: ROCK CREEK TRIBUTARY

0.3 MI N OF CEDAR LANE, Montgomery, MD

Built 2016 Load: 42.1 t ADT: 718

LITTLE SENECA PKWY

Good

Over: LITTLE SENECA CREEK TRIB

0.5 MI. E. OF MD 355, Montgomery, MD

Built 2011 Load: 42.2 t ADT: 10,542

Ramp NW to MD200WB

Good

Over: US29 Ramp NB&SE MD200

0.4 Mi S of Briggs Chaney, Montgomery, MD

Built 2011 Load: 42.2 t ADT: 2,294

SNOUFFER SCHOOL RO

Good

Over: CABIN BRANCH

1.3 MI N OF MD124, Montgomery, MD

Built 2020 Load: 42.4 t ADT: 18,315

MD 200 (ICC) WB

Good

Over: Northwest Branch

1.40 Mi West of MD650, Montgomery, MD

Built 2010 Load: 43.1 t ADT: 32,683

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.