Total bridges
818
Public highway bridges in Middlesex County
County profile · official public datasets
Middlesex County, MA
818 public highway bridges tracked in the FHWA National Bridge Inventory: 20.7% rated Good, 68.2% Fair, 11.1% Poor.
- 818
- Public bridges
- 20.7%
- Good condition
- 11.1%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Middlesex County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.
- 11th
- of 13 on Poor share
- 11.1%
- Poor-condition share
- 818
- public highway bridges
- 1958
- 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.
Middlesex County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Middlesex County ranks #11 of 13 Massachusetts counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.1%). Middlesex County, Massachusetts contains 818 public highway bridges. Roughly 20.7% are rated “Good,” 68.2% “Fair,” and 11.1% “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.
Good condition
20.7%
169 of 818 rated 7-9
Fair condition
68.2%
558 of 818 rated 5-6
Poor condition
11.1%
91 of 818 rated 4 or below
In-state Poor-share rank
#11 of 13
Among Massachusetts counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 818 NBI-tracked bridges by lowest applicable component rating.
Good 20.7% (169)
Fair 68.2% (558)
Poor 11.1% (91)
Middlesex County's Poor-condition bridges carry 3,395,813 vehicle crossings a day
That is 12.7% of the county's reported daily bridge traffic on 11.1% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 37,317 crossings a day against 21,585 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 818 of 818 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
70.5% of Middlesex County's bridges have passed the 50-year mark
577 of the 818 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 20.7% 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 5.9% of the county's Poor-condition bridge traffic
I 93 over I 95 /ST128, built 1957, carries 200,824 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 91-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 3,395,813 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Middlesex County's bridges were built
818 bridges with a recorded construction year, grouped by decade
- pre-1900 68
Built before 1900
68 bridges
- 1900s 45
1900–1909
45 bridges
- 1910s 21
1910–1919
21 bridges
- 1920s 23
1920–1929
23 bridges
- 1930s 39
1930–1939
39 bridges
- 1940s 25
1940–1949
25 bridges
- 1950s
1950–1959
179 bridges
- 1960s
1960–1969
161 bridges
- 1970s 33
1970–1979
33 bridges
- 1980s 29
1980–1989
29 bridges
- 1990s 45
1990–1999
45 bridges
- 2000s
2000–2009
90 bridges
- 2010s 44
2010–2019
44 bridges
- 2020s 16
2020–2029
16 bridges
What this shows Construction peaked in the 1950s, when 179 of the county's bridges still in the inventory were built, which is 21.9% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1958) matches the Massachusetts average (1961).
How Middlesex County compares with Massachusetts's closest counties by inventory size
The 5 Massachusetts counties nearest Middlesex County in number of bridges, with their condition splits. Its 11.1% Poor share is the 5th-lowest of these 6. Its average build year of 1958 against a peer-group mean of 1961 is in line with the group.
Showing the 5 closest of 12 Massachusetts counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Worcester County | 1,014 | 25.5% | 66.9% | 7.6% | 1963 |
| Middlesex County (this page) | 818 | 20.7% | 68.2% | 11.1% | 1958 |
| Suffolk County | 489 | 22.7% | 67.7% | 9.6% | 1967 |
| Berkshire County | 450 | 34.7% | 57.6% | 7.8% | 1961 |
| Hampden County | 428 | 17.1% | 75.5% | 7.5% | 1956 |
| Essex County | 395 | 15.9% | 66.8% | 17.2% | 1957 |
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 Middlesex 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 Middlesex County, both outside Massachusetts so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MA (818 bridges here).
- Montgomery County, PA · 828 bridges
- Duval County, FL · 831 bridges
- Davidson County, TN · 832 bridges
- Lancaster County, PA · 801 bridges
Similar average build year
Nearest mean year-built outside MA (1958 here).
- Bucks County, PA · avg 1958 · 699 bridges
- Butte County, CA · avg 1958 · 437 bridges
- Cowley County, KS · avg 1958 · 337 bridges
- Marin County, CA · avg 1958 · 207 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (558)
HWY CHURCH ST
FairOver: OTHER CENTRAL RAIL TRAIL
.32 KM NELY CONANT RD, Middlesex, MA
Built 1911 Load: 60.6 t ADT: 7,758
HWY SCHOOL ST
FairOver: WATER MERRIMACK RIVER
S. OF VFW HIGHWAY, Middlesex, MA
Built 1917 Load: 60.9 t ADT: 20,800
US 3 SB
FairOver: HWY FARM RD
0.25 MI S TREBLECOVE RD, Middlesex, MA
Built 2004 Load: 61.0 t ADT: 59,224
US 3 NB
FairOver: HWY FARM RD
0.25 MI S TREBLECOVE RD, Middlesex, MA
Built 2004 Load: 61.0 t ADT: 53,663
HWY SYCAMORE ST
FairOver: RR MBTA/BMRR
1.3 KM W OF JCT SR28&38, Middlesex, MA
Built 1902 Load: 61.1 t ADT: 1,160
US 3 NB
FairOver: ST 40 GROTON RD
RTE 3 AT RTE 40, Middlesex, MA
Built 2004 Load: 61.2 t ADT: 51,585
HWY PLAIN ST
FairOver: WATER RIVER MEADOW BROOK
0.25 MI E RT 110, Middlesex, MA
Built 1960 Load: 63.6 t ADT: 12,850
HWY HERRICK RD
FairOver: TR GREEN LINE D
OVER GREEN LINE, Middlesex, MA
Built 1907 Load: 63.6 t ADT: 4,267
HWY PROSPECT ST
FairOver: WATER CHARLES RIVER
.6 MI. S. MAIN ST., Middlesex, MA
Built 1888 Load: 63.6 t ADT: 35,200
I 95 /ST128
FairOver: RR BMRR/MBTA
1.2 MI ELY RT 129, Middlesex, MA
Built 1948 Load: 63.7 t ADT: 127,837
HWY KEARNEY SQ
FairOver: WATER EASTERN CANAL
MERRIMACK & E.MERRIMACK, Middlesex, MA
Built 1835 Load: 64.8 t ADT: 15,000
HWY RECREATN RD
FairOver: ST128 SERVICE RD
0.8 KM SO MASS PIKE, Middlesex, MA
Built 1950 Load: 66.3 t ADT: 1,034
HWY PLEASANT ST
FairOver: WATER CHARLES RIVER
.1 MI SOUTH OF ST. 16, Middlesex, MA
Built 1861 Load: 67.5 t ADT: 9,000
HWY CONCORD RD
FairOver: OTHER CENTRAL RAIL TRAIL
0.6 KM NWLY BSTON POST RD, Middlesex, MA
Built 1911 Load: 67.7 t ADT: 5,431
HWY MYST VAL PKY
FairOver: WATER ALEWIFE BROOK
.4 MI N OF BROADWAY, Middlesex, MA
Built 1908 Load: 67.8 t ADT: 16,200
ST117 GREAT RD
FairOver: WATER ASSABET RIVER
0.4 MILES E STOW T. L., Middlesex, MA
Built 1900 Load: 67.8 t ADT: 12,464
ST113 PLEASANT ST
FairOver: WATER BEAVER BK WEST STR
.8 KM N RIVERSIDE ST, Middlesex, MA
Built 1855 Load: 68.3 t ADT: 17,123
HWY LAKEVIEW AVE
FairOver: WATER BEAVER BROOK
.40 KM E OF MAMMOTH RD, Middlesex, MA
Built 1850 Load: 71.9 t ADT: 9,250
HWY SUMMER ST
FairOver: WATER SHAWSHEEN RIVER
2.5 MI E OF SOUTH RD, Middlesex, MA
Built 1959 Load: 72.3 t ADT: 26,897
US 3 NB
FairOver: HWY MAIN ST
2 MI. NW DRUM HILL, Middlesex, MA
Built 2004 Load: 76.5 t ADT: 51,000
HWY DRAKE RD
FairOver: OTHER MINUTEMAN BIKE PTH
0.4 MI W OF PARK AVE, Middlesex, MA
Built 1995 Load: 77.6 t ADT: 400
ST 3 SB
FairOver: HWY LEDGE RD
1.1 MI N OF RTE 40, Middlesex, MA
Built 2004 Load: 77.9 t ADT: 40,287
ST 3 NB
FairOver: HWY LEDGE RD
1.1 M. NO. OF RT 40, Middlesex, MA
Built 2004 Load: 77.9 t ADT: 41,426
HWY WALNUT ST
FairOver: WATER ASSABET RIVER
.1 MI. S. OF ST-62, Middlesex, MA
Built 1922 Load: 78.2 t ADT: 2,500
HWY EAST ST
FairOver: WATER STRONG WATER BROOK
0.85MI E OF LIVINGSTON ST, Middlesex, MA
Built 2008 Load: 86.3 t ADT: 22,050
HWY LAWRENCE ST
FairOver: WATER RIVER MEADOW BROOK
NEAR CONCORD RIVER, Middlesex, MA
Built 1910 Load: 89.0 t ADT: 9,200
ST 38 MAIN ST
FairOver: WATER ABERJONA RIVER
.16 KM. E. OF RT. 38, Middlesex, MA
Built 1915 Load: 92.0 t ADT: 10,732
ST 31 STATE RD
FairOver: WATER WILLARD BROOK
AT ST 119 INTERSECTION, Middlesex, MA
Built 1908 Load: 95.3 t ADT: 4,671
ST113 PLEASANT ST
FairOver: WATER BEAVER BK EAST STR
.8 KM N RIVERSIDE ST, Middlesex, MA
Built 1855 Load: 95.8 t ADT: 17,123
HWY BROOK ST
FairOver: WATER NASHOBA BROOK
.25 MI. W OF RTE. 2A, Middlesex, MA
Built 1938 Load: 99.2 t ADT: 7,200
HWY RIVER ST
FairOver: WATER FORT POND BROOK
@ CORNER OF CARRIAGE ST, Middlesex, MA
Built 1937 Load: 99.9 t ADT: 800
ST 27 MAIN ST
FairOver: WATER FORT POND BROOK
1 MI. S. OF SCHOOL ST, Middlesex, MA
Built 1900 Load: 99.9 t ADT: 9,069
HWY RIVER ST
FairOver: WATER FORT POND BROOK
.6 MI. E. OF ST. 27, Middlesex, MA
Built 1981 Load: 99.9 t ADT: 3,500
HWY RIVER ST
FairOver: WATER MYSTIC RIVER
TOWN LINE MED ARL, Middlesex, MA
Built 1938 Load: 99.9 t ADT: 5,302
ST 60 MEDFORD ST
FairOver: WATER MYSTIC RIVER
TOWN LINE MED ARL, Middlesex, MA
Built 1936 Load: 99.9 t ADT: 24,310
HWY MDDLSEX TPK
FairOver: WATER SHAWSHEEN RIVER
.7 M SE OF BILLERICA, Middlesex, MA
Built 1975 Load: 99.9 t ADT: 18,000
ST129 SALEM RD
FairOver: WATER SHAWSHEEN RIVER
0.75 MI E SALEM & BALDWIN, Middlesex, MA
Built 1932 Load: 99.9 t ADT: 10,600
US 3
FairOver: WATER RIVER MEADOW BRK
0.25 MI S RT 3 & RT 110, Middlesex, MA
Built 1959 Load: 99.9 t ADT: 126,338
US 3
FairOver: WATER STONY BROOK
1 MI NW DRUM HILL, Middlesex, MA
Built 1959 Load: 99.9 t ADT: 100,800
HWY ELM ST
FairOver: WATER SUDBURY RIVER
1.2 KM NE RT 2 & RT 62, Middlesex, MA
Built 1874 Load: 99.9 t ADT: 13,100
ST 62 MAIN ST
FairOver: WATER POWER CANAL
2.4 KM SW RT 2, Middlesex, MA
Built 1885 Load: 99.9 t ADT: 14,400
HWY MONUMENT ST
FairOver: WATER CONCORD RIVER
2.9 KM N OF RT 2, Middlesex, MA
Built 1877 Load: 99.9 t ADT: 6,607
I 90
FairOver: WATER SUDBURY RIVER
.1 MI EAST OF I-495, Middlesex, MA
Built 1957 Load: 99.9 t ADT: 102,416
ST110 CHURCH
FairOver: WATER CONCORD RIVER
0.25 MI W RT 38, Middlesex, MA
Built 1858 Load: 99.9 t ADT: 13,000
HWY MILL ST
FairOver: WATER ASSABET RIVER
0.2 MI. N. OF RT. 62, Middlesex, MA
Built 1937 Load: 99.9 t ADT: 1,040
ST117 GREAT RD
FairOver: WATER MILL CANAL
INTER OF WINTER& RT117, Middlesex, MA
Built 1850 Load: 99.9 t ADT: 13,011
ST 9 BOYLSTON ST
FairOver: WATER CHARLES RIVER
NEWTON-WELLESLEY TWN LINE, Middlesex, MA
Built 1900 Load: 99.9 t ADT: 51,270
ST 9 BOYLSTON ST
FairOver: WATER HEMLOCK GORGE
AT QUINOBEQUIN RD, Middlesex, MA
Built 1932 Load: 99.9 t ADT: 56,450
I 90
FairOver: HWY CHARLES ST
.1 MI E.CHARLES RV S10, Middlesex, MA
Built 1964 Load: 99.9 t ADT: 86,719
HWY TOWNSEND RD
FairOver: WATER MULPUS BROOK
.1 MI N OF ST-2A, Middlesex, MA
Built 1961 Load: 99.9 t ADT: 2,050
Read our methodology - how this data is sourced, computed, and verified.
Related
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.