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.

Total bridges

108

Public highway bridges in Sierra County

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

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).

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

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.

Bridge inventory size and condition shares for Sierra County and the 5 New Mexico counties closest to it in inventory size
County Bridges Poor
Chaves County 120 2.5%
Quay County 118 6.8%
Sierra County (this page) 108 4.6%
Luna County 107 0%
Catron County 101 4%
Grant County 99 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 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).

Similar average build year

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

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

All 108 Good 30 Fair 73 Poor 5

All bridges (108)

I-25 NBL

Fair

Over: Palomas Creek

8.1 M N Jct NM-152/I-25, Sierra, NM

Built 1968 Load: 32.7 t ADT: 8,617

I-25 SBL

Fair

Over: Palomas Creek

8.1 M N Jct NM-152/I-25, Sierra, NM

Built 1968 Load: 32.7 t ADT: 8,617

I-25 NBL/SBL

Fair

Over: SOUTH CANYON

5.2 MILES SOUTH OF EXIT, Sierra, NM

Built 1967 Load: 32.7 t ADT: 5,583

I-25 NBL/SBL

Fair

Over: LUMBER CANYON

3.1 MILES S OF EXIST 100, Sierra, NM

Built 1967 Load: 32.7 t ADT: 5,583

I-25 NBL/SBL

Fair

Over: CEDAR CANYON

3.1 MI N OF NM-181, Sierra, NM

Built 1967 Load: 32.7 t ADT: 6,271

I-25 NBL/SBL

Fair

Over: CANADA HONDA

0.9 MI S WILLIAMSBURG EXT, Sierra, NM

Built 1968 Load: 32.7 t ADT: 8,617

I-25 NBL/SBL

Fair

Over: COUNTY RD-B079

0.6 MILES COUNTY RD B-79, Sierra, NM

Built 1968 Load: 32.7 t ADT: 8,617

I-25 NBL/SBL

Fair

Over: LOCAL ROAD/1ST STREET

0.3 MI N WILLIAMSBURG, Sierra, NM

Built 1970 Load: 32.7 t ADT: 5,633

L-00011

Fair

Over: UNNAMED WATERWAY

0.5 M N I-25/WILLIAMSBURG, Sierra, NM

Built 1970 Load: 32.7 t ADT: 4,994

I-25 NBL/SBL

Fair

Over: UNNAMED WATERWAY

1.6 MI S OF NM-152, Sierra, NM

Built 1966 Load: 32.7 t ADT: 7,700

NM-27

Fair

Over: JUARLOSA CREEK

10.7 MI S OF JCT NM-152, Sierra, NM

Built 1974 Load: 32.7 t ADT: 94

WSMR P RT 7

Fair

Over: STORM DRAINAGE

17 MILES N FROM RR7B0011, Sierra, NM

Built 2012 Load: 32.7 t ADT: 100

I-25 NBL

Fair

Over: Yapple Canyon

2.7 Mi N T or C N Interch, Sierra, NM

Built 1970 Load: 33.7 t ADT: 3,216

I-25 SBL

Fair

Over: Yapple Canyon

2.7 Mi N T or C N Interch, Sierra, NM

Built 1970 Load: 33.7 t ADT: 3,216

I-25 SB

Fair

Over: NM-181

Junction of I-25/NM-181, Sierra, NM

Built 1967 Load: 34.0 t ADT: 6,271

NM-152

Fair

Over: Unnamed Waterway

9.3 M w of Jct. I-25, Sierra, NM

Built 1988 Load: 34.3 t ADT: 403

I-25 NBL

Fair

Over: Green Horn Arroyo

0.6 M S Jct I-25/NM-152, Sierra, NM

Built 1966 Load: 36.9 t ADT: 7,700

I-25 SBL

Fair

Over: Green Horn Arroyo

.6 M S Jct NM-152/I-25, Sierra, NM

Built 1966 Load: 36.9 t ADT: 7,700

I-25 NBL

Fair

Over: Local Road

2.6 Mi N of Jct NM-1/X-91, Sierra, NM

Built 1979 Load: 37.9 t ADT: 5,583

I-25 SBL

Fair

Over: Local Road

2.6 Mi N of Jct NM-1/X-91, Sierra, NM

Built 1979 Load: 37.9 t ADT: 5,583

NM-181

Fair

Over: CUCHILLO NEGRO CREEK

2.0 MI N OF NM-51/T OR C, Sierra, NM

Built 1993 Load: 44.9 t ADT: 3,467

WSMR P RT 7

Fair

Over: STORM DRAINAGE

15 MILES N FROM RR7B0010, Sierra, NM

Built 1965 Load: 56.1 t ADT: 100

E GRAND PERCHA RD.

Fair

Over: ARREY IRRIGATION CANAL

1.79 M NE ARREY/PERCHA DM, Sierra, NM

Built 1936 Load: 63.5 t ADT: 66

NM-187

Good

Over: UNNAMED WATERWAY

9.7 MI N OF NM-152, Sierra, NM

Built 1933 Load: 24.5 t ADT: 491

L-00011

Good

Over: I-25 NBL/SBL

North T or C Interchange, Sierra, NM

Built 1970 Load: 26.9 t ADT: 1,146

NM-546

Good

Over: I-25 NBL and SBL

0.7 M E Jct NM-187/I-25, Sierra, NM

Built 1965 Load: 32.4 t ADT: 231

NM-152

Good

Over: Percha Creek

6.7 Mi E of Kingston, Sierra, NM

Built 1994 Load: 32.4 t ADT: 290

NM-187

Good

Over: Rio Grande

2.7 Mi N of NM-546/Derry, Sierra, NM

Built 2005 Load: 32.4 t ADT: 1,030

I-25 NBL/SBL

Good

Over: UNNAMED WATERWAY

5.9 MI N OF DONA ANA CL, Sierra, NM

Built 1965 Load: 32.7 t ADT: 7,049

I-25 NBL

Good

Over: Rio Grande River

1.3 Mi S Jct I-25/NM-187, Sierra, NM

Built 2003 Load: 32.7 t ADT: 7,049

I-25 SBL

Good

Over: Rio Grande River

1.3 Mi S Jct. I-25/NM-187, Sierra, NM

Built 2003 Load: 32.7 t ADT: 7,049

51-A013

Good

Over: HACKBERRY DRAW

7.O M S JCT NM-51, Sierra, NM

Built 2009 Load: 32.7 t ADT: 87

51-A013

Good

Over: MC LENDON DRAW

9.6 M S JCT NM-51, Sierra, NM

Built 2009 Load: 32.7 t ADT: 87

51-A001

Good

Over: Flood Control Ditch

1.8 MI. EAST ON BROAD AVE, Sierra, NM

Built 2003 Load: 32.7 t ADT: 66

CORIZNE STREET

Good

Over: FLOOD CONTROL DITCH

1.8 MI EAST BROAD AVE, Sierra, NM

Built 2003 Load: 32.7 t ADT: 66

51-A001

Good

Over: FLOOD CONTROL DITCH

1.8 MI EAST BROAD AVE, Sierra, NM

Built 2003 Load: 32.7 t ADT: 66

NM-51

Good

Over: ASH CANYON

5.75 MI E OF LOOP-11 T /C, Sierra, NM

Built 2009 Load: 32.7 t ADT: 129

NM152

Good

Over: Unnamed Waterway

7.3 miles west jct I-25, Sierra, NM

Built 1988 Load: 32.7 t ADT: 403

WSMR P Rt 6

Good

Over: Salt Creek

7 MI WSMR P RT 6 & 7 INTR, Sierra, NM

Built 2019 Load: 32.7 t ADT: 100

NM-51

Good

Over: RIO GRANDE

3.1 MI E OF LOOP-11\TRUTH, Sierra, NM

Built 2007 Load: 33.6 t ADT: 631

51-013

Good

Over: ALEMAN DRAW

12.7 MI S OF NM-51 ENGLE, Sierra, NM

Built 2009 Load: 34.1 t ADT: 87

WSMR P RT 316

Good

Over: SALT CREEK

N OF RR316B1, Sierra, NM

Built 2021 Load: 35.0 t ADT: 25

NM-51

Good

Over: CUCHILLO CREEK

2.2 MI E OF LOOP-11/TRUTH, Sierra, NM

Built 2007 Load: 35.3 t ADT: 1,592

NM-152

Good

Over: Percha Creek

3.2 Mi East of Kingston, Sierra, NM

Built 2021 Load: 37.9 t ADT: 288

NM-152

Good

Over: Middle Fork Percha Creek

1.2 Mi East of Kingston, Sierra, NM

Built 2021 Load: 38.2 t ADT: 288

NM-181

Good

Over: Yapple Canyon

5.3 M N of T OR C/exit 83, Sierra, NM

Built 2020 Load: 39.9 t ADT: 159

A-013

Good

Over: Yost Arroya

21.8 M N fo I-25 Ex 32, Sierra, NM

Built 2018 Load: 45.4 t ADT: 230

I-25 NBL/SBL

Good

Over: GREEN CANYON

1.75 M N OF NM-546, Sierra, NM

Built 2003 Load: 47.4 t ADT: 7,049

NM-187

Good

Over: MONTOYA ARROYO

4.9 MI N OF DONA ANA C/L, Sierra, NM

Built 2021 Load: 49.1 t ADT: 1,022

NM-187

Good

Over: UNNAMED WATERWAY

4.5 MI N OF DONA ANA C/L, Sierra, NM

Built 2021 Load: 50.3 t ADT: 1,022

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.