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 28

Good

Over: BATCHELLORS RUN

0.65 MILE WEST OF MD 182, Montgomery, MD

Built 1999 Load: 43.5 t ADT: 24,340

MD 109

Good

Over: BR OF LITTLE MONOCACY RI

1.74 M S OFCOMUS ROAD, Montgomery, MD

Built 2003 Load: 43.5 t ADT: 1,732

FATHER HURLEY BOUL

Good

Over: CENTURY BOULEVARD

0.2 MI SW OF JCT I-270, Montgomery, MD

Built 1995 Load: 43.5 t ADT: 14,319

FATHER HURLEY BOUL

Good

Over: CENTURY BOULEVARD

0.2 MI SW OF JCT I-270, Montgomery, MD

Built 1995 Load: 43.5 t ADT: 13,713

Ramp EN

Good

Over: MD 200 (ICC) US29 Rp SE

MD200EB Ramp EN to US29NB, Montgomery, MD

Built 2011 Load: 43.5 t ADT: 5,902

MD200 (ICC) WB

Good

Over: NORTH BRANCH ROCK CREEK

1.51 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 44.0 t ADT: 30,827

MD 97 SB

Good

Over: MD 200 (ICC)

0.59 MI NORTH OF MD 28, Montgomery, MD

Built 2010 Load: 44.0 t ADT: 27,660

MD 200 (ICC) WB

Good

Over: Ramp NW

0.4 mi W of Briggs Chaney, Montgomery, MD

Built 2011 Load: 44.0 t ADT: 21,574

RAMP WS

Good

Over: MD 200/US29 Ramp EB

1 Mi. E of Old Columbia, Montgomery, MD

Built 2011 Load: 44.0 t ADT: 2,397

SNOUFFER SCHOOL RO

Good

Over: CABIN BRANCH

1.3 MI N OF MD124, Montgomery, MD

Built 2020 Load: 44.1 t ADT: 18,315

IS 370 WBR

Good

Over: CRABBS BRANCH WAY

5.84 MILE WEST OF MD 97, Montgomery, MD

Built 2010 Load: 44.4 t ADT: 78,741

BRINK ROAD

Good

Over: TRIB TO GOSHEN BRANCH

1.0 MILES WEST OF MD 124, Montgomery, MD

Built 2007 Load: 44.4 t ADT: 11,066

LAYHILL RD (MD182)

Good

Over: MD 200 (ICC)

2.79 MI WEST OF MD650, Montgomery, MD

Built 2010 Load: 44.4 t ADT: 14,607

MD 200 (ICC) EB

Good

Over: NORTHWEST BRANCH

2.54 MI WEST OF MD650, Montgomery, MD

Built 2010 Load: 44.4 t ADT: 32,786

MD 200 (ICC) WB

Good

Over: Northwest Branch

2.54 Mi West of MD650, Montgomery, MD

Built 2010 Load: 44.4 t ADT: 32,683

IS 370 EBR

Good

Over: CRABBS BRANCH WAY

5.84 MILE WEST OF MD 355, Montgomery, MD

Built 2010 Load: 44.9 t ADT: 78,741

MD 195

Good

Over: LONG BRANCH

AT LONG BRANCH PARKWAY, Montgomery, MD

Built 2005 Load: 44.9 t ADT: 13,190

IS 270 RAMP C(5)

Good

Over: IS 370 & RAMP B

1.53 MILE SOUTH OF MD 117, Montgomery, MD

Built 1988 Load: 45.4 t ADT: 15,251

MD 200 (ICC) EB

Good

Over: Shady Grove Road

4.86 MI W. OF MD 97, Montgomery, MD

Built 2010 Load: 45.4 t ADT: 31,652

Ramp WN to US29 NB

Good

Over: MD 200 Ramp NW

0.4 mi S Briggs Chaney Rd, Montgomery, MD

Built 2011 Load: 45.4 t ADT: 309

MD 119

Good

Over: GUNNERS BR CSXT RR

.5 MI S OF MIDDLEBROOK RD, Montgomery, MD

Built 1987 Load: 45.8 t ADT: 6,955

WAYNE AVENUE

Good

Over: SLIGO CREEK

AT MANCHESTER AVENUE, Montgomery, MD

Built 1960 Load: 45.8 t ADT: 19,450

IS 370

Good

Over: MD 355

1.18 MILE EAST OF IS 270, Montgomery, MD

Built 1989 Load: 46.7 t ADT: 79,062

WATTS BRANCH PARKW

Good

Over: WATTS BRANCH

0.2 MI S OF HURLEY AVE, Montgomery, MD

Built 1970 Load: 46.7 t ADT: 3,704

MD 200 (ICC) WB

Good

Over: Bonifant Road & NW Branc

2.07 Mi West of MD 650, Montgomery, MD

Built 2010 Load: 47.2 t ADT: 32,683

IS 495

Good

Over: MD 187 (OLD GEORGETOWN R

1.1 MILES WEST OF MD 355, Montgomery, MD

Built 2003 Load: 47.6 t ADT: 113,030

IS 270Y HOV RAMP

Good

Over: IS 270Y MEDIAN

AT WESTLAKE TERRACE, Montgomery, MD

Built 2003 Load: 47.6 t ADT: 114,000

US 29 NBR

Good

Over: MD 198

1.53 M S OF HOWARD CO LNE, Montgomery, MD

Built 2004 Load: 47.6 t ADT: 49,203

MONTROSE PARKWAY

Good

Over: OLD FARM CREEK

1.0 MILE EAST OF I-270, Montgomery, MD

Built 2007 Load: 47.6 t ADT: 28,776

PRESERVE PARKWAY

Good

Over: TRIBUTARY TO CABIN JOHN

0.1M S OF WOOTTON PKWY, Montgomery, MD

Built 1999 Load: 47.6 t ADT: 2,840

MD 97 (GEORGIA AV)

Good

Over: RANDOLPH ROAD

1.4 MI E OF MD 185, Montgomery, MD

Built 2018 Load: 48.0 t ADT: 46,114

IS 495 RAMP K(4)

Good

Over: IS 495X NBR

0.48 MI W OF MD 190, Montgomery, MD

Built 1962 Load: 48.1 t ADT: 8,755

REDLAND ROAD

Good

Over: MD 200 (ICC)

4.38 MI W OF MD 97, Montgomery, MD

Built 2009 Load: 48.1 t ADT: 12,649

MD 200 (ICC) EB

Good

Over: Northwest Branch

1.40 Mi West of MD 650, Montgomery, MD

Built 2010 Load: 48.1 t ADT: 32,786

LYTTONSVILLE PLACE

Good

Over: PURPLE LINE

1 MILES NORTH OF MD 410, Montgomery, MD

Built 2019 Load: 48.6 t ADT: 10,523

MD 355

Good

Over: GREAT SENECA CREEK

1.32 MILES N OF MD 124, Montgomery, MD

Built 2000 Load: 49.0 t ADT: 31,050

HOWARD CHAPEL RD

Good

Over: PATUXENT RIVER

1.7 MI NORTH OF MD 650, Montgomery, MD

Built 2002 Load: 49.0 t ADT: 563

MD 187

Good

Over: IS 270

0.404 M N/DEMOCRACY BLVD, Montgomery, MD

Built 2002 Load: 49.4 t ADT: 45,401

MD 929A & MD 929B

Good

Over: US 29

0.17 MILE EAST OF MD 929C, Montgomery, MD

Built 2006 Load: 49.4 t ADT: 36,072

DRIVEWAY OFF AINTR

Good

Over: WATTS BRANCH

WOOTTONS MILL PARK, Montgomery, MD

Built 2009 Load: 49.4 t ADT: 20

LONGMEAD CROSSING

Good

Over: MD 200 (ICC)

3.61 MI WEST OF MD650, Montgomery, MD

Built 2010 Load: 49.4 t ADT: 6,790

MD 121

Good

Over: IS 270

0.64 MILE SOUTH OF MD 355, Montgomery, MD

Built 1997 Load: 49.9 t ADT: 13,714

DUSTIN ROAD

Good

Over: US 29

0.05 M E OF COLUMBIA PIKE, Montgomery, MD

Built 2003 Load: 49.9 t ADT: 999

PARK VALLEY ROAD

Good

Over: SLIGO CREEK

AT SLIGO CR PKWY, Montgomery, MD

Built 2019 Load: 49.9 t ADT: 1,126

MD 97 NB

Good

Over: MD 200 (ICC)

0.59 MI NORTH OF MD 28, Montgomery, MD

Built 2010 Load: 50.3 t ADT: 23,218

MD 200 (ICC) Ramp

Good

Over: MD 200 (ICC) Ramp SE

0.2 mi W US29/MD200 I/C, Montgomery, MD

Built 2010 Load: 50.3 t ADT: 2,449

I-370 WBR

Good

Over: IS-370 RP1 MD200 RP7

5.67 MI WEST OF MD97, Montgomery, MD

Built 2010 Load: 50.8 t ADT: 39,531

WHITE GROUND ROAD

Good

Over: BUCKLODGE BRANCH

2 MILES NORTH OF MD 28, Montgomery, MD

Built 2012 Load: 50.8 t ADT: 823

WATKINS MILL ROAD

Good

Over: WHETSTONE RUN

0.5 MILES EAST OF MD 355, Montgomery, MD

Built 1997 Load: 50.8 t ADT: 8,397

WATKINS MILL ROAD

Good

Over: CSX RAILROAD

.28 MI. N. OF MD 117, Montgomery, MD

Built 2006 Load: 50.8 t ADT: 2,136

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.