Top 10 US Counties by Total Bridge Count (FHWA NBI)
PlainBridges ranks US counties by total NBI bridge count. Rendered server-side from the counties aggregation table.
Research period:
Research question
Which individual US counties carry the largest bridge inventories under the National Bridge Inventory, and how concentrated is the national total at county level?
Methodology
This ranking reflects the data currently in our database, sourced from the agency referenced in the citation below and updated automatically as new filings are processed.
Coverage and exclusions: the source agency occasionally suppresses values for confidentiality, small sample size, or quality control, and suppressed rows are excluded from this ranking rather than shown as zero. If the agency later revises a figure, the revised value replaces the old one automatically the next time our data is refreshed.
Data provenance: we pull each release as it becomes available and normalize it into our database; a later release simply supersedes the one before it, so readers never see a mix of old and new figures on the same page.
Comparability across years: when the source agency revises its release schedule, definitions, or coverage, we note the affected years on the methodology page so readers can compare like-with-like rather than across a changed measurement.
Editorial governance: a named editor reviews every ranking page before publication (see the byline above). If an entity disputes a figure attributed to it, corrections are checked against the official source record before any change is made.
Every number on this page can be traced back to its source by following the entity links and the citation below, so independent verification never requires anything beyond the original public source.
See the methodology page for the complete ETL pipeline, source vintage, and column lineage.
Top 10 US Counties by Total Bridge Count (FHWA NBI)
Live data: reflects the current dataset
The ranked top 10
Every row below reflects the current 10-record dataset. Reload the page after new data is processed to see the latest values.
| # | County | State | Total bridges | Poor condition |
|---|---|---|---|---|
| 1 | Harris | Texas | 4,030 | 18 |
| 2 | Los Angeles | California | 3,937 | 88 |
| 3 | Dallas | Texas | 3,231 | 18 |
| 4 | Tarrant | Texas | 2,617 | 6 |
| 5 | Bexar | Texas | 2,343 | 5 |
| 6 | Maricopa | Arizona | 2,203 | 3 |
| 7 | Cook | Illinois | 2,185 | 144 |
| 8 | San Diego | California | 1,707 | 27 |
| 9 | Travis | Texas | 1,544 | 2 |
| 10 | San Bernardino | California | 1,465 | 80 |
Source: Federal Highway Administration (FHWA) - FHWA NBI county-level aggregations. Values reflect the current dataset, refreshed as new filings are processed. Federal Highway Administration (FHWA) - FHWA NBI county-level aggregations. Values reflect the current dataset, refreshed as new filings are processed.
Findings
Top entity in the ranking
The top-ranked record in this dataset is Harris, with a value of 4,030 on the Total bridges column. The full top-10 set is rendered in the table above. Every value derives from the underlying counties table; no number is hardcoded into this page. When the Federal Highway Administration (FHWA) publishes a revision and our ETL pipeline reingests, the ranking and the prose around it update on the next page load.
Distribution shape
The gap between the top-ranked record (4,030) and the 10th-ranked record (1,465) characterizes how concentrated the top of the distribution is. Where the top value is many multiples of the median value of the visible set, the population is highly concentrated, a small number of entities accumulate the bulk of the measured quantity. Where the top and bottom of the visible set are close together, the distribution is relatively flat across the top end. The full distribution beyond this top-10 cut is summarized in the aggregate context section below and explored in the linked entity profiles.
Aggregate context
Across the full counties population, the aggregate query returns the following summary statistics. These anchors situate the top-10 ranking against the underlying population: how many records exist in total, what the sum of the ranking column is across all qualifying rows, and what the mean per-record value looks like. The methodology page documents the exact filter applied by the aggregate query (records with null or zero values on the ranking column are excluded). The aggregate row is computed by the same database engine that renders the ranking above, against the same snapshot.
Source provenance
The records in this ranking originate from Federal Highway Administration (FHWA), specifically the FHWA NBI county-level aggregations. PlainBridges compiles the agency's published vintage into our own database and rebuilds the site whenever the source refreshes, so these numbers stay current within hours of a new release rather than sitting frozen in a static export. The methodology page documents the source URL, the vintage date, and the transformation steps applied.
Why this ranking matters
Rankings like this one let a reader scan a population quickly and identify outliers, concentrations, and patterns that warrant deeper investigation. The detail pages linked from each entity in the table above give the full per-entity context: time-series history where available, related metrics from adjacent tables, and links onward to the underlying source records. The methodology page explains how an entity earns inclusion in the dataset and how the ranking column is computed at the source.
What this analysis cannot tell us
County-level bridge counts reflect the NBI county_code field as reported by source agencies. Counties with low totals are filtered from the Poor-condition comparison to reduce small-denominator swings. County inventory size reflects road-network coverage and ownership, not population. Poor means the lowest applicable major-component rating is 4 or below; the aggregate does not establish funding decisions, agency performance, or live safety.
Secondary cut from the same source
Top 10 counties by absolute count of Poor-condition bridges (counties with ≥100 bridges)
Sources
- FHWA, National Bridge Inventory (NBI) - https://www.fhwa.dot.gov/bridge/nbi.cfm
- FHWA Bridge Conditions by State and County - https://www.fhwa.dot.gov/bridge/britab.cfm
Every figure on PlainBridge 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.