Coverage and row definition
The CSV contains 624 rows: 52 nation/state/DC geographies times twelve census years. Each row identifies internal ID, official code, name, census year, integer population, unit, measurement type, original source URL, publication date and a boundary note. It describes census counts, not July annual estimates or a later estimates base.
Source: Census Historical Population Change Data (1910–2020), published April 26, 2021. The table was checked and retained September 30, 2026. Our extract selects resident-population counts for the nation, states and DC; regional percent-change rows and Puerto Rico are outside this dataset. The original table remains the authoritative interpretation reference.
Historical definitions and dates
These observations retain historical geographic definitions. They are not interpolated to a standardized 2025 boundary, and changing territory and census definitions matter when interpreting the national series. Alaska and Hawaii have observations from before statehood; the presence of a row in the modern state list does not imply it was a state in every census year.
Reference dates also differ historically: April 15, 1910; January 1, 1920; and April 1 from 1930 onward. The file uses census_year rather than inventing a uniform July reference date. This site does not calculate exact annualized rates between these historical counts without an explicit elapsed-time convention.
Reuse and revisions
Census employee-created statistical works are generally outside U.S. copyright protection under the Census public-access policy (DS027). Original publication text and branding have separate terms.
The underlying federal statistical observations retain Census attribution. Review the source catalog and citation text. The frozen extract is packaged with the initial annual-release downloads but has its own historical collection identifier and measurement type. A later correction must receive a new version rather than silently changing this file.
County and city decennial histories before 2010 are not included. For 2010–2020, use the separate intercensal series; for 2020–2025, the annual PEP dataset. Keep the series separate in charts and analysis.