County profile · official public datasets

McHenry County, IL

227 public highway bridges tracked in the FHWA National Bridge Inventory: 41.4% rated Good, 38.3% Fair, 20.3% Poor.

227
Public bridges
41.4%
Good condition
20.3%
Poor condition

The verdict

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

McHenry County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

99th
of 102 on Poor share
20.3%
Poor-condition share
227
public highway bridges
1983
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.

McHenry County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, McHenry County ranks #99 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 20.3%). McHenry County, Illinois contains 227 public highway bridges. Roughly 41.4% are rated “Good,” 38.3% “Fair,” and 20.3% “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

227

Public highway bridges in McHenry County

Good condition

41.4%

94 of 227 rated 7-9

Fair condition

38.3%

87 of 227 rated 5-6

Poor condition

20.3%

46 of 227 rated 4 or below

In-state Poor-share rank

#99 of 102

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

Condition distribution

Share of 227 NBI-tracked bridges by lowest applicable component rating.

Good
41.4% (94)
Fair
38.3% (87)
Poor
20.3% (46)

McHenry County's Poor-condition bridges carry 69,075 vehicle crossings a day

That is 5.9% of the county's reported daily bridge traffic on 20.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,502 crossings a day against 7,359 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 227 of 227 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

34.4% of McHenry County's bridges have passed the 50-year mark

78 of the 227 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 41.4% 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 16.6% of the county's Poor-condition bridge traffic

US 12 over NIPPERSINK CR OVERFL, built 1939, carries 11,500 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 46-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 69,075 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When McHenry County's bridges were built

227 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 2010s, when 44 of the county's bridges still in the inventory were built, which is 19.4% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year (1983) matches the Illinois average (1979).

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

How McHenry County compares with Illinois's closest counties by inventory size

The 5 Illinois counties nearest McHenry County in number of bridges, with their condition splits. Its 20.3% Poor share is the 6th-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1981 is in line with the group.

Showing the 5 closest of 101 Illinois counties eligible for comparison.

Bridge inventory size and condition shares for McHenry County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Washington County 233 6%
Douglas County 232 1.3%
Clark County 230 4.8%
Jackson County 228 6.6%
McHenry County (this page) 227 20.3%
Woodford County 223 10.3%

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 McHenry 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 McHenry County, both outside Illinois so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IL (227 bridges here).

Similar average build year

Nearest mean year-built outside IL (1983 here).

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

All 227 Good 94 Fair 87 Poor 46

All bridges (227)

BUNKER HILL ROAD

Poor

Over: RUSH CREEK

0.8 MI W OF IL 23, McHenry, IL

Built 1962 Load: 19.1 t ADT: 100

KUNDE RD

Poor

Over: KISHWAUKEE RIVER

0.5 MI W OF FRANKLIN, McHenry, IL

Built 1985 Load: 19.1 t ADT: 75

BARREVILLE RD

Poor

Over: Sleepy Hollow Creek

0.4 MI N OF AMES RD, McHenry, IL

Built 1957 Load: 19.4 t ADT: 1,350

THORNE RD

Poor

Over: KISHWAUKEE RIV

3.0 MI W OF MARENGO, McHenry, IL

Built 1992 Load: 19.8 t ADT: 275

BULL VALLEY ROAD

Poor

Over: BOONE CREEK

0.2 MI E OF CURRAN R, McHenry, IL

Built 1969 Load: 21.4 t ADT: 9,300

SOUTH ST RD

Poor

Over: FRANKLINVILLE CR

0.1MI E OF ROSE FM, McHenry, IL

Built 1983 Load: 21.7 t ADT: 2,050

MELODY LANE

Poor

Over: SILVER CREEK

0.09M.W. OFIL-47, McHenry, IL

Built 1984 Load: 22.0 t ADT: 1,050

US 12

Poor

Over: N BR NIPPERSINK CRK

0.5 M S E OF IL 31, McHenry, IL

Built 1990 Load: 22.4 t ADT: 8,250

STREIT ROAD

Poor

Over: PISCASAW CREEK

0.4 MI E OF COUNTY, McHenry, IL

Built 1959 Load: 22.4 t ADT: 425

DARTMOOR DRIVE

Poor

Over: BOONE CREEK

0.6 MI E CURRAN, McHenry, IL

Built 1998 Load: 23.0 t ADT: 2,550

NORTH UNION ROAD

Poor

Over: KISHWAUKEE RIVER

0.3 MI W OF IL 47, McHenry, IL

Built 1959 Load: 24.6 t ADT: 875

THAYER ROAD

Poor

Over: NIPPERSINK CREEK

0.3 MI W OF IL 47, McHenry, IL

Built 1975 Load: 25.3 t ADT: 800

MS-3020 Center St

Poor

Over: Stream

.7MI SW ROBERTS RD, McHenry, IL

Built 1991 Load: 25.6 t ADT: 575

SULLIVAN ROAD

Poor

Over: TRIB N BR KISWKE RIV

0.1 MI N COLLINS RD, McHenry, IL

Built 1965 Load: 26.6 t ADT: 100

HARMONY ROAD

Poor

Over: COON CREEK

0.3 MI E OF PAYNE RD, McHenry, IL

Built 1980 Load: 26.6 t ADT: 725

QUEEN ANNE RD

Poor

Over: NIPPERSINK CREEK

2.7 MI N CHARLES RD, McHenry, IL

Built 1960 Load: 26.9 t ADT: 575

MCCUE ROAD

Poor

Over: KISHWAUKEE RIVER

0.6 MI S OF IL 176, McHenry, IL

Built 1973 Load: 27.5 t ADT: 400

TR-73 (Allendale R

Poor

Over: NIPPERSINK CR

0.4 MI E OF IL 47, McHenry, IL

Built 1978 Load: 27.5 t ADT: 850

CH-43 Millstream R

Poor

Over: S Br Kishwaukee Rvr

0.4 MI N ILL 176, McHenry, IL

Built 1964 Load: 28.2 t ADT: 1,700

HAEGERS BEND RD

Poor

Over: FOX RIV INLET

0.3 MI NW ALGONQUIN, McHenry, IL

Built 1986 Load: 28.2 t ADT: 650

CH43 (MILLSTREAM R

Poor

Over: KISHWAUKEE RIVER

0.5 MI. N. ILL. 176, McHenry, IL

Built 1964 Load: 28.5 t ADT: 1,700

ROOT ROAD

Poor

Over: RUSH CREEK

0.1 MI N OF CH 30, McHenry, IL

Built 1900 Load: 29.2 t ADT: 100

CHARLES RD

Poor

Over: Slough Creek

AT NELSON RD, McHenry, IL

Built 1947 Load: 29.8 t ADT: 6,300

QUEEN ANNE RD

Poor

Over: BR OF NIPPERSINK CR

2.4 MI N OF CHARLES, McHenry, IL

Built 1960 Load: 36.6 t ADT: 575

OAKWOOD DRIVE

Poor

Over: BOONE CREEK

.5 M S 1201 M W 31, McHenry, IL

Built 1971 Load: 42.8 t ADT: 1,150

US 12

Poor

Over: NIPPERSINK CR OVERFL

0.3 M N OF CO LINE, McHenry, IL

Built 1939 Load: 45.7 t ADT: 11,500

Bay Road

Poor

Over: Unnamed Tributary

0.5 mi S of Edgewood, McHenry, IL

Built 1980 Load: 89.1 t ADT: 1,550

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.