Where does NC County Map get its population data?

Population counts come from the U.S. Census Bureau — the 2020 Decennial Census (Table P1) as the authoritative baseline, refreshed against the most recent Vintage population estimates for inter-censal years. We do not use third-party aggregators when a Census file is available.

Where do the county boundary shapes come from?

County polygons are derived from the U.S. Census Bureau's 2020 cartographic boundary files at the 1:500,000 resolution (counties layer). Those files are public domain. We cross-check boundary edges against NC OneMap — the State of North Carolina's official GIS portal — before publishing.

How is land area calculated?

Land area uses the CENSUSAREA field from the same Census cartographic boundary files, expressed in square miles and rounded to the nearest whole square mile for display.

How often is the data updated?

Reference data (county seats, regions, formation dates, adjacencies) is reviewed annually and whenever a relevant statute changes. Population figures are re-checked annually against the latest Census Vintage estimates and refreshed completely after each Decennial Census.

How are county adjacencies determined?

Bordering-county lists are computed directly from the boundary geometry — two counties are listed as neighbors if their polygons share an edge of more than a few meters in the Census TIGER/Line shapefiles. They are not hand-curated, so we don't accidentally miss small or coastal borders.

Do you use AI to write content?

No published page is AI-generated and shipped as-is. AI tools may assist with drafting, summarising sources, or fact-checking, but every page is reviewed and edited by a human against primary sources before it goes live. Our editorial policy spells this out in more detail.

How do I report an error in a statistic?

Use our contact page. Please include the URL of the page in question and a link to the primary source supporting your correction. We log every correction with the date and what changed, and post a dated note at the foot of the affected page for material corrections.

Trust

Methodology

Every number, boundary, and date on NC County Map traces back to a primary source. This page documents which sources we use, how we verify them, how often we refresh, and what we do when something is wrong.

Last reviewed: June 2026 · Sources: U.S. Census Bureau, NC OneMap

Primary data sources

NC County Map publishes only data we can trace to a primary government or authoritative academic source. The four pillars are the U.S. Census Bureau, NC OneMap (the State of North Carolina's GIS portal), the U.S. Bureau of Labor Statistics, and the NC Department of the Secretary of State.

U.S. Census Bureau — population (Decennial P1; Vintage estimates), cartographic boundary files, land/water area, TIGER/Line topology.
NC OneMap (nconemap.gov) — state-curated GIS for parcels, transportation, and statewide reference layers; used to cross-check boundary geometry.
U.S. Bureau of Labor Statistics — county-level employment and unemployment context when published.
NC Department of the Secretary of State — county formation dates and historical records of county changes; supplemented by David Leroy Corbitt, The Formation of the North Carolina Counties, 1663–1943.
NC Association of County Commissioners and individual county government websites — county seats, county manager and elected official information, and links to official county records.

Population and demographics

The authoritative population number for each NC county is the U.S. Census Bureau's Decennial Census, Table P1 (Total Population). Between decennial releases, we update against the Census's annual Vintage population estimates, which use vital statistics, tax records, and migration data to refresh county-level totals.

We do not mix sources within a single statistic. A population number on this site is always either the Decennial baseline or the most recent Vintage estimate — never a blended value. Where a Vintage refresh has moved a number materially, the affected page carries an "updated" date that reflects the actual editorial review.

Boundaries and land area

All county polygons rendered on NC County Map are derived from the U.S. Census Bureau's cartographic boundary files for counties at the 1:500,000 resolution. Those files are public domain and are the same boundary source used by federal mapping products, USDA, and most academic GIS work in the United States.

We project the boundaries with a geographic Albers-style projection tuned for North Carolina before rendering them as SVG. Land area is taken from the CENSUSAREA field of the same cartographic file and displayed in square miles, rounded to the nearest whole square mile. We test edge cases (coastal counties, sound and Outer Banks geometry) against NC OneMap before publishing.

County adjacency (bordering counties)

The "neighboring counties" list on every county page is computed directly from Census TIGER/Line geometry. Two counties are listed as neighbors when their polygons share a contiguous edge of more than a few meters. This avoids two common errors: hand-curated lists that miss small or coastal borders, and naïve "same-region" lists that include counties without an actual shared boundary.

The list is strictly limited to the 100 NC counties — we do not include adjacent counties in Virginia, Tennessee, South Carolina, or Georgia in the on-page list, though those state-line crossings are noted in editorial text where relevant.

Formation dates and history

Each county's date of establishment, parent counties, and successor history come from the NC Department of the Secretary of State and from David Leroy Corbitt's The Formation of the North Carolina Counties, 1663–1943, the standard academic reference on the subject. Where a county's history involves a renaming or an early colonial precursor, we note the precursor name in the editorial text.

Update cadence

Reference data (seats, regions, formation dates, adjacencies) — reviewed at least annually and whenever the NC General Assembly changes a relevant law.
Population — re-checked annually against the latest Census Vintage estimates; full refresh after every Decennial Census.
Boundaries — re-rendered when Census publishes a new cartographic boundary file.
Editorial content — reviewed on a rolling basis; the "updated" date on each page reflects the most recent human review, not an auto-generated timestamp.

Verification and review

Every statistical claim in our editorial copy is verified against the primary source listed above before publication. New pages and substantial rewrites are reviewed by a second editor; small edits and copy fixes are tracked in our version control. Our editorial policy describes our use of AI assistance (allowed for research; never published unedited) and our independence from advertisers.

Limitations

NC County Map is a reference site, not a legal record. Property boundaries, voter registration, court filings, and tax records should always be confirmed with the county office that holds the official record — most commonly the Register of Deeds, the Board of Elections, the Clerk of Court, or the Tax Administrator. Our maps are cartographic representations, not survey-grade documents.

Corrections

If you spot an error — a wrong county seat, an outdated population, a mis-drawn border, a broken official link — please tell us. Use the contact page and include the page URL plus a link to the primary source that supports the correction. We log every correction internally with the date and reason, and post a dated note at the foot of the affected page for any material change.

Frequently asked questions

Where does NC County Map get its population data?: Population counts come from the U.S. Census Bureau — the 2020 Decennial Census (Table P1) as the authoritative baseline, refreshed against the most recent Vintage population estimates for inter-censal years. We do not use third-party aggregators when a Census file is available.
Where do the county boundary shapes come from?: County polygons are derived from the U.S. Census Bureau's 2020 cartographic boundary files at the 1:500,000 resolution (counties layer). Those files are public domain. We cross-check boundary edges against NC OneMap — the State of North Carolina's official GIS portal — before publishing.
How is land area calculated?: Land area uses the CENSUSAREA field from the same Census cartographic boundary files, expressed in square miles and rounded to the nearest whole square mile for display.
How often is the data updated?: Reference data (county seats, regions, formation dates, adjacencies) is reviewed annually and whenever a relevant statute changes. Population figures are re-checked annually against the latest Census Vintage estimates and refreshed completely after each Decennial Census.
How are county adjacencies determined?: Bordering-county lists are computed directly from the boundary geometry — two counties are listed as neighbors if their polygons share an edge of more than a few meters in the Census TIGER/Line shapefiles. They are not hand-curated, so we don't accidentally miss small or coastal borders.
Do you use AI to write content?: No published page is AI-generated and shipped as-is. AI tools may assist with drafting, summarising sources, or fact-checking, but every page is reviewed and edited by a human against primary sources before it goes live. Our editorial policy spells this out in more detail.
How do I report an error in a statistic?: Use our contact page. Please include the URL of the page in question and a link to the primary source supporting your correction. We log every correction with the date and what changed, and post a dated note at the foot of the affected page for material corrections.