Total bridges
108
Public highway bridges in Sierra County
County profile · official public datasets
Sierra County, NM
108 public highway bridges tracked in the FHWA National Bridge Inventory: 27.8% rated Good, 67.6% Fair, 4.6% Poor.
- 108
- Public bridges
- 27.8%
- Good condition
- 4.6%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Sierra County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 19th
- of 32 on Poor share
- 4.6%
- Poor-condition share
- 108
- 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.
Sierra County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Sierra County ranks #19 of 32 New Mexico counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.6%). Sierra County, New Mexico contains 108 public highway bridges. Roughly 27.8% are rated “Good,” 67.6% “Fair,” and 4.6% “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
27.8%
30 of 108 rated 7-9
Fair condition
67.6%
73 of 108 rated 5-6
Poor condition
4.6%
5 of 108 rated 4 or below
In-state Poor-share rank
#19 of 32
Among New Mexico counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 108 NBI-tracked bridges by lowest applicable component rating.
Good 27.8% (30)
Fair 67.6% (73)
Poor 4.6% (5)
Sierra County's Poor-condition bridges carry 9,053 vehicle crossings a day
That is 2.6% of the county's reported daily bridge traffic on 4.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,811 crossings a day against 1,691 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 108 of 108 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
72.2% of Sierra County's bridges have passed the 50-year mark
78 of the 108 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 27.8% 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 77.9% of the county's Poor-condition bridge traffic
I-25 SBL/NBL over UNNAMED WATERWAY, built 1965, carries 7,049 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 5-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 9,053 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Sierra County's bridges were built
108 bridges with a recorded construction year, grouped by decade
- 1920s 3
1920–1929
3 bridges
- 1930s 17
1930–1939
17 bridges
- 1950s 1
1950–1959
1 bridges
- 1960s
1960–1969
43 bridges
- 1970s 17
1970–1979
17 bridges
- 1980s 2
1980–1989
2 bridges
- 1990s 3
1990–1999
3 bridges
- 2000s 13
2000–2009
13 bridges
- 2010s 3
2010–2019
3 bridges
- 2020s 6
2020–2029
6 bridges
What this shows Construction peaked in the 1960s, when 43 of the county's bridges still in the inventory were built, which is 39.8% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1971) matches the New Mexico average (1973).
How Sierra County compares with New Mexico's closest counties by inventory size
The 5 New Mexico counties nearest Sierra County in number of bridges, with their condition splits. Its 4.6% Poor share is the 5th-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1965 is 6 years newer.
Showing the 5 closest of 31 New Mexico counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Chaves County | 120 | 33.3% | 64.2% | 2.5% | 1970 |
| Quay County | 118 | 34.7% | 58.5% | 6.8% | 1968 |
| Sierra County (this page) | 108 | 27.8% | 67.6% | 4.6% | 1971 |
| Luna County | 107 | 26.2% | 73.8% | 0% | 1961 |
| Catron County | 101 | 45.5% | 50.5% | 4% | 1962 |
| Grant County | 99 | 20.2% | 76.8% | 3% | 1963 |
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 Sierra 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 Sierra County, both outside New Mexico so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside NM (108 bridges here).
- Lassen County, CA · 108 bridges
- Pulaski County, IL · 108 bridges
- West Feliciana County, LA · 108 bridges
- Brown County, MN · 108 bridges
Similar average build year
Nearest mean year-built outside NM (1971 here).
- Wayne County, MI · avg 1971 · 1,026 bridges
- Baltimore County, MD · avg 1971 · 783 bridges
- Washington County, PA · avg 1971 · 655 bridges
- Linn County, OR · avg 1971 · 566 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (108)
NM-187
FairOver: SECO CREEK
2.2 MI N OF JCT NM-152, Sierra, NM
Built 1933 Load: 14.7 t ADT: 491
NM-436
FairOver: GARFIELD CANAL
0.1 MI W OF JCT NM-187, Sierra, NM
Built 1953 Load: 18.0 t ADT: 207
NM-187
FairOver: TRUJILLO CANYON
6.2 MI N OF DONA ANA C/L, Sierra, NM
Built 1929 Load: 19.6 t ADT: 1,030
NM-187
FairOver: PERCHA CREEK
9.4 MI N OF DONA ANA C/L, Sierra, NM
Built 1929 Load: 21.2 t ADT: 280
NM-187
FairOver: CANADA HONDA
11.1 MI N OF NM-152, Sierra, NM
Built 1933 Load: 24.3 t ADT: 491
NM-1
FairOver: UNNAMED WATERWAY
0.3 W & N OF I-25 EXT#101, Sierra, NM
Built 1938 Load: 24.3 t ADT: 25
I-25 NBL/SBL
FairOver: ARAGON WASH
1.62 MI N OF EXIT 92, Sierra, NM
Built 1938 Load: 24.5 t ADT: 5,583
I-25 NBL/SBL
FairOver: MITCHELL CANYON
0.26 MI N OF EXIT 92, Sierra, NM
Built 1938 Load: 24.5 t ADT: 5,583
NM-181
FairOver: CEDAR CANYON
1.25 MI S OF EXIT-89/I-25, Sierra, NM
Built 1939 Load: 24.5 t ADT: 68
NM-1
FairOver: SAN JOSE CANYON
0.3 MILES WEST OF EXIT 10, Sierra, NM
Built 1938 Load: 24.5 t ADT: 25
NM-1
FairOver: UNNAMED WATERWAY
0.5 W & N OF I-25/EXT100, Sierra, NM
Built 1938 Load: 24.5 t ADT: 25
I-25 NBL/SBL
FairOver: PENASCO-CANYON
20.7 MI N OF JCT NM-51, Sierra, NM
Built 1938 Load: 24.5 t ADT: 5,583
NM-187
FairOver: UNNAMED WATERWAY
5.8 M N OF NM-152, Sierra, NM
Built 1933 Load: 24.5 t ADT: 491
NM-187
FairOver: NORTH KELLY CANYON
4.9 M N OF NM-152, Sierra, NM
Built 1933 Load: 24.5 t ADT: 491
NM-187
FairOver: SOUTH KELLY CANYON
4.8 MI N OF NM-152, Sierra, NM
Built 1933 Load: 24.5 t ADT: 491
I-25 NBL
FairOver: Cuchillo Negro Creek/Rd
0.9 M N TorC Interchange, Sierra, NM
Built 1970 Load: 25.6 t ADT: 3,216
I-25 SBL
FairOver: Cuchillo Negro Creek/lRd
0.9 M N I-25/T or C, Sierra, NM
Built 1970 Load: 25.6 t ADT: 3,216
NM-52
FairOver: Unnamed Waterway
5.58 MI E OF NM-181, Sierra, NM
Built 1995 Load: 26.1 t ADT: 229
I-25 NBL
FairOver: Local Rd 51Z004/Mud Sprg
0.7 M N Williamsburg, Sierra, NM
Built 1970 Load: 30.2 t ADT: 5,633
I-25 SBL
FairOver: Local Rd/Mud Spring Aryo
0.7 M N Jct Loop 001/I-25, Sierra, NM
Built 1970 Load: 30.2 t ADT: 5,633
NM-187
FairOver: Animas Creek
1.0 M N Jct NM-152/NM-187, Sierra, NM
Built 1933 Load: 30.8 t ADT: 491
I-25 NB
FairOver: NM-181
Junction I-25 and NM-181, Sierra, NM
Built 1967 Load: 30.8 t ADT: 8,183
NM-27
FairOver: TRUJILLO CANYON
3.5 MI S OF JCT NM-152, Sierra, NM
Built 1973 Load: 31.8 t ADT: 94
I-25 NBL
FairOver: NM-152
Junction I-25/NM-152, Sierra, NM
Built 1966 Load: 32.2 t ADT: 7,585
I-25 SBL
FairOver: NM-152
Junction I-25/NM-152, Sierra, NM
Built 1966 Load: 32.2 t ADT: 7,585
I-25 NBL
FairOver: Country Club Rd
3.3 M N Jct Loop 001/I-25, Sierra, NM
Built 1970 Load: 32.2 t ADT: 5,633
I-25 SBL
FairOver: Country Club Rd
3.3 M N Jct Loop 001/I-25, Sierra, NM
Built 1970 Load: 32.2 t ADT: 5,633
NM-187
FairOver: Palomas Creek
Nm-187 mile post 32.4, Sierra, NM
Built 1932 Load: 32.4 t ADT: 491
NM-187
FairOver: I-25 NBL/SBL
4.2 M S Jct. I-25/NM-187, Sierra, NM
Built 1965 Load: 32.4 t ADT: 1,030
NM-1
FairOver: I-25 NBL and SBL
Junction I-25 and NM-1, Sierra, NM
Built 1967 Load: 32.4 t ADT: 19
FR-2030
FairOver: I-25 NBLS/SBLS
8.74 M N Jct. I-25/NM-1, Sierra, NM
Built 1967 Load: 32.4 t ADT: 24
FR-2027
FairOver: I-25 NBLS/SBLS
5.2 Mi N Jct I-25/NM-181, Sierra, NM
Built 1967 Load: 32.4 t ADT: 89
FR-2022
FairOver: I-25 NBL and I-25 SBL
7.7 Mi N of Jct NM-152, Sierra, NM
Built 1968 Load: 32.4 t ADT: 485
L-00011
FairOver: UNNAMED WATERWAY
0.7 M N I-25/WILLIAMSBURG, Sierra, NM
Built 1970 Load: 32.7 t ADT: 4,994
NM-152
FairOver: PERCHA CREEK
0.8 MI W JCT NM 27/NM-152, Sierra, NM
Built 1961 Load: 32.7 t ADT: 290
NM-152
FairOver: PERCHA CREEK
0.3 MI E JCT NM 27/NM 152, Sierra, NM
Built 1961 Load: 32.7 t ADT: 403
NM-152
FairOver: MIDDLE PERCHA CREEK
0.3 MI E OF KINGSTON, Sierra, NM
Built 1963 Load: 32.7 t ADT: 290
NM-152
FairOver: MIDDLE PERCHA CREEK
0.7 MI E OF KINGSTON, Sierra, NM
Built 1963 Load: 32.7 t ADT: 290
L-00011
FairOver: UNNAMED WATERWAY
2.4 mi NE Exit 75/I-25, Sierra, NM
Built 1963 Load: 32.7 t ADT: 4,994
I-25 NBL
FairOver: Percha Creek
0.34 Mi N of Jct NM-187, Sierra, NM
Built 1965 Load: 32.7 t ADT: 7,700
I-25 SBL
FairOver: Percha Creek
0.34 Mi N of Jct NM-187, Sierra, NM
Built 1965 Load: 32.7 t ADT: 7,700
I-25 NBL/SBL
FairOver: UNNAMED WATERWAY
14.9 MI N OF NM-26/HATCH, Sierra, NM
Built 1965 Load: 32.7 t ADT: 7,049
I-25 NBL
FairOver: Animas Creek
0.9 Mi N of Jct NM-152, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,585
I-25 SBL
FairOver: Amimas Creek
0.9 M N Jct NM-152/I-25, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,585
I-25 NBL
FairOver: Arroyo Seco
2.4 M N Jct NM-152/I-25, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,585
I-25 SBL
FairOver: Arroyo Seco
2.4 M N Jct NM-152/I-25, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,585
I-25 NBL/SBL
FairOver: UNNAMED WATERWAY
1.0 MI S OF NM-152, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,700
I-25 NBL/SBL
FairOver: COUNTY RD-B050
0.8 MI N OF NM-152, Sierra, NM
Built 1966 Load: 32.7 t ADT: 7,585
I-25 NBL
FairOver: Kings Canyon
6.3 M N Jct NM-152/I-25, Sierra, NM
Built 1968 Load: 32.7 t ADT: 7,585
I-25 SBL
FairOver: Kings Canyon
6.3 M N Jct NM-152/I-25, Sierra, NM
Built 1968 Load: 32.7 t ADT: 7,585
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.