County profile · official public datasets

Frederick County, MD

486 public highway bridges tracked in the FHWA National Bridge Inventory: 43.2% rated Good, 54.1% Fair, 2.7% Poor.

486
Public bridges
43.2%
Good condition
2.7%
Poor condition

The verdict

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

Frederick County posts a top-quartile lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 25%
lowest Poor share in state
2.7%
Poor-condition share
486
public highway bridges
1971
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.

Frederick County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Frederick County ranks #6 of 24 Maryland counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.7%). Frederick County, Maryland contains 486 public highway bridges. Roughly 43.2% are rated “Good,” 54.1% “Fair,” and 2.7% “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

486

Public highway bridges in Frederick County

Good condition

43.2%

210 of 486 rated 7-9

Fair condition

54.1%

263 of 486 rated 5-6

Poor condition

2.7%

13 of 486 rated 4 or below

In-state Poor-share rank

#6 of 24

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

Condition distribution

Share of 486 NBI-tracked bridges by lowest applicable component rating.

Good
43.2% (210)
Fair
54.1% (263)
Poor
2.7% (13)

Frederick County's Poor-condition bridges carry 17,033 vehicle crossings a day

That is 0.3% of the county's reported daily bridge traffic on 2.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,310 crossings a day against 7,809 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 486 of 486 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

47.5% of Frederick County's bridges have passed the 50-year mark

231 of the 486 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 43.2% 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 39.6% of the county's Poor-condition bridge traffic

SHOOKSTOWN ROAD over CARROLL CREEK, built 1911, carries 6,750 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 13-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 17,033 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Frederick County's bridges were built

486 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 104 of the county's bridges still in the inventory were built, which is 21.4% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1971) matches the Maryland average (1972).

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

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

The 5 Maryland counties nearest Frederick County in number of bridges, with their condition splits. Its 2.7% Poor share is the 2nd-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1975 is in line with the group.

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

Bridge inventory size and condition shares for Frederick County and the 5 Maryland counties closest to it in inventory size
County Bridges Poor
Prince George's County 576 3.1%
Montgomery County 515 4.9%
Frederick County (this page) 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 Frederick 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 Frederick County, both outside Maryland so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MD (486 bridges here).

Similar average build year

Nearest mean year-built outside MD (1971 here).

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

All 486 Good 210 Fair 263 Poor 13

All bridges (486)

BLACKS MILL ROAD

Fair

Over: BIG HUNTING CREEK

WEST OF LAYMAN RD INT, Frederick, MD

Built 1914 Load: 10.4 t ADT: 450

BENNIES HILL ROAD

Fair

Over: CATOCTIN CREEK

0.65 MI EAST OF MD 17, Frederick, MD

Built 1880 Load: 13.2 t ADT: 131

KEYSVILLE ROAD

Fair

Over: TOMS CREEK

2.0 MI NORTHEAST OF MD 76, Frederick, MD

Built 1876 Load: 13.6 t ADT: 451

MD 550

Fair

Over: CABBAGE RUN

1.39 MILES NORTH OF MD 26, Frederick, MD

Built 1939 Load: 14.5 t ADT: 2,785

STEVENS ROAD

Fair

Over: HUNTING CREEK

WEST OF OLD FREDERICK RD, Frederick, MD

Built 1914 Load: 14.5 t ADT: 135

HOLTER ROAD

Fair

Over: HOLLOW CREEK

1 MILE SOUTHEAST OF MD 17, Frederick, MD

Built 1920 Load: 15.4 t ADT: 3,333

MAINTENANCE ROAD

Fair

Over: BLUE BLAZES CREEK

US-15N WEST ON MC-77 TO, Frederick, MD

Built 1960 Load: 15.4 t ADT: 50

CROW ROCK ROAD

Fair

Over: MIDDLE CREEK

AT MD 17 INTERSECTION, Frederick, MD

Built 1897 Load: 16.3 t ADT: 460

SUMANTOWN ROAD

Fair

Over: CATOCTIN CREEK

1.5 MI W OLD MIDDLETOWN R, Frederick, MD

Built 1900 Load: 16.3 t ADT: 124

STATION ROAD

Fair

Over: CATOCTIN CREEK

0.5 MI W OF OLD HAGERSTOW, Frederick, MD

Built 1920 Load: 16.8 t ADT: 133

OLD MILL ROAD

Fair

Over: OWENS CREEK

0.87 MILES SOUTH OF MD 77, Frederick, MD

Built 1882 Load: 17.2 t ADT: 360

GRIMES ROAD

Fair

Over: TOMS CREEK

0.5 MILES S OF SIXES ROAD, Frederick, MD

Built 1914 Load: 18.6 t ADT: 170

SIMPSONS MILL ROAD

Fair

Over: LITTLE PIPE CREEK

1.12 MI N OF GOOD INTENT, Frederick, MD

Built 1890 Load: 18.6 t ADT: 200

SIXES BRIDGE ROAD

Fair

Over: MONOCACY RIVER

2.5 MI S OF KEYSVILLE RD, Frederick, MD

Built 1910 Load: 19.0 t ADT: 198

MD 17

Fair

Over: CATOCTIN CREEK

0.6 M S OF MAERK ROAD, Frederick, MD

Built 1934 Load: 19.5 t ADT: 5,450

MD 17

Fair

Over: CATOCTIN CREEK

0.6 MILE SOUTH OF IS 70, Frederick, MD

Built 1928 Load: 20.4 t ADT: 3,891

US 15

Fair

Over: POTOMAC RIVER CSX C&O

POINT OF ROCKS, Frederick, MD

Built 1939 Load: 20.9 t ADT: 20,473

MD 17

Fair

Over: MIDDLE CREEK

1.13 MILES N OF MD 383, Frederick, MD

Built 1923 Load: 20.9 t ADT: 5,891

US 40 ALT

Fair

Over: CATOCTIN CREEK

0.05 M E OF MARKER ROAD, Frederick, MD

Built 1923 Load: 20.9 t ADT: 9,212

MD 75

Fair

Over: PLEASANT BRANCH

1.71 MILES N OF MD 355, Frederick, MD

Built 1930 Load: 21.8 t ADT: 7,952

US 15 NBR

Fair

Over: FISHING CREEK

0.07 MI N OF POWELL RD, Frederick, MD

Built 1972 Load: 22.2 t ADT: 43,080

DOLLYHYDE ROAD

Fair

Over: NORTH FORK LINGANORE CRK

0.6 MI N OF EMERS BURR RD, Frederick, MD

Built 1960 Load: 22.7 t ADT: 151

POINT OF ROCKS ROA

Fair

Over: C&O CANAL

0.3 MILES FROM POTOMAC RI, Frederick, MD

Built 1890 Load: 23.2 t ADT: 159

MD 144FA & CO RD

Fair

Over: LONG BRANCH

0.504 M W OF CAR. CO LINE, Frederick, MD

Built 1954 Load: 23.6 t ADT: 13,511

MD 383

Fair

Over: CATOCTIN CREEK

1.52 MILES N OF MD 180, Frederick, MD

Built 1953 Load: 23.6 t ADT: 1,550

UTICA ROAD

Fair

Over: FISHING CREEK

0.12 MI W OLD FREDERICK R, Frederick, MD

Built 1860 Load: 23.6 t ADT: 298

MD 355

Fair

Over: MONOCACY RIVER

2.29 MILES SOUTH OF MD 85, Frederick, MD

Built 1930 Load: 24.0 t ADT: 12,583

MD 17

Fair

Over: CSX TRANS. POTOMAC MUN

ON VIRGINIA LINE, Frederick, MD

Built 1953 Load: 24.5 t ADT: 6,073

FRIENDS CREEK ROAD

Fair

Over: FRIENDS CREEK

1.5 MI NE OF EYLER VALLEY, Frederick, MD

Built 1910 Load: 24.5 t ADT: 123

ROAD

Fair

Over: OWENS CREEK

Take Hwy 77 3 miles west, Frederick, MD

Built 1970 Load: 24.5 t ADT: 160

MD 550

Fair

Over: DORCUS BRANCH

0.74 MILE SOUTH OF MD 194, Frederick, MD

Built 1925 Load: 24.9 t ADT: 3,541

US 340

Fair

Over: CATOCTIN CREEK

0.63 MILE EAST OF MD 180, Frederick, MD

Built 1961 Load: 24.9 t ADT: 28,982

RIDGE ROAD

Fair

Over: IS 70

1.57 MI W OF US 40, Frederick, MD

Built 1972 Load: 25.4 t ADT: 1,342

PRIVATE LANE

Fair

Over: FISHING CREEK

200 W OF MOUNTAINDALE RD, Frederick, MD

Built 2007 Load: 25.9 t ADT: 50

MD 478

Fair

Over: BR OF POTOMAC RIVER

0.23 MILE EAST OF MD 180, Frederick, MD

Built 1926 Load: 26.3 t ADT: 2,471

BULLFROG ROAD

Fair

Over: MONOCACY RIVER

0.6 MI S OF BOLLINGER SCL, Frederick, MD

Built 1908 Load: 26.3 t ADT: 324

WOODVILLE ROAD

Fair

Over: TALBOT BRANCH

AT TALBOT RUN RD INTERSEC, Frederick, MD

Built 1961 Load: 26.3 t ADT: 890

OLD FREDERICK ROAD

Fair

Over: OWENS CREEK

0.3 MI S OF MD RTE 77, Frederick, MD

Built 1869 Load: 26.8 t ADT: 843

HESSONG BRIDGE RD

Fair

Over: LITTLE HUNTING CREEK

AT BLACKS MILL RD INT, Frederick, MD

Built 1905 Load: 27.7 t ADT: 980

NORMAN BALM ENTRAN

Fair

Over: ABANDONED RR

0.1MI NW OF 1728 N MARKET, Frederick, MD

Built 1920 Load: 28.1 t ADT: 5

HARBAUGH VALLEY RO

Fair

Over: BRANCH OF FRIENDS CREEK

0.15 MI NE OF MD RTE 550, Frederick, MD

Built 1985 Load: 28.6 t ADT: 713

DOGWOOD DRIVE

Fair

Over: TRIBUTARY NO. 8

0.7 MI EAST OF MD 355, Frederick, MD

Built 1986 Load: 28.6 t ADT: 2,485

US 40

Fair

Over: BRANCH OF ROCK CREEK

.036 MILE EAST OF US 40AL, Frederick, MD

Built 1947 Load: 29.0 t ADT: 47,332

UNIONVILLE ROAD

Fair

Over: WELDON CREEK

AT BLACK ANKLE RD INT, Frederick, MD

Built 1929 Load: 29.0 t ADT: 493

IS 70 RAMP A & E

Fair

Over: US 15/US 340

0.37 MILE EAST OF MD 180, Frederick, MD

Built 1968 Load: 29.5 t ADT: 13,542

US 40

Fair

Over: CATOCTIN CREEK

0.17 MILE WEST OF MD 17, Frederick, MD

Built 1936 Load: 29.9 t ADT: 5,432

MD 77

Fair

Over: BEAVER BRANCH

0.63 MILE WEST OF MD 76, Frederick, MD

Built 1928 Load: 29.9 t ADT: 1,211

IS 270 WBR(RAMP 1)

Fair

Over: IS 70 EBR

0.09 MILE SOUTH OF US 40, Frederick, MD

Built 1967 Load: 29.9 t ADT: 14,067

IS 70

Fair

Over: BUSH CREEK

0.84 MILE EAST OF MD 75, Frederick, MD

Built 1954 Load: 30.4 t ADT: 69,020

MD 26

Fair

Over: DOLLYHYDE CREEK

0.34 MILE EAST OF MD 31, Frederick, MD

Built 1932 Load: 30.4 t ADT: 5,482

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.