Census Bureau & Federal Census

The decennial census — conducted every 10 years by the U.S. Census Bureau under Title 13 of the U.S. Code and mandated by Article I, Section 2 of the Constitution — is the most politically consequential statistical exercise the federal government undertakes. Census data directly determines: the apportionment of 435 House seats among the states (seven states gained or lost seats after the 2020 census); state and local redistricting of congressional, state legislative, and local districts; and the allocation of more than $1.5 trillion in annual federal funding across programs that use census data to distribute grants (Medicaid, highway funds, Title I education aid, and hundreds of others). Participation is legally required (13 U.S.C. § 221), though enforcement is essentially nonexistent. Census responses are strictly confidential under Title 13 — individual data cannot be shared with law enforcement, immigration authorities, or any other agency for 72 years (after which historical records become public). The American Community Survey (ACS) provides annual sample-based data on demographics, income, housing, and employment between decennial censuses. The 2020 census was marked by controversy over the Trump administration's attempt to add a citizenship question (blocked by the Supreme Court in 2019), COVID-related field operations disruptions, and post-count accuracy disputes that continue to affect downstream estimates. The next decennial census is 2030.

Current Law (2026)

Legal Authority

• 13 U.S.C. § 141 — Population and housing census (decennial count on April 1; Secretary determines questions; mid-decade estimates authorized)
• 13 U.S.C. § 131 — Census of business and manufactures (every 5 years: manufacturing, mining, retail, services, transportation)
• 13 U.S.C. § 161 — Census of governments (every 5 years: state and local government taxes, revenues, expenditures, debt, employees)
• 13 U.S.C. § 181 — Annual population estimates (current population data for every state, county, and locality)
• 13 U.S.C. § 191 — Geographic scope (all states, D.C., and U.S. territories)
• 13 U.S.C. § 9 — Confidentiality (individual census data cannot be used against respondents; protected from legal process)
• 13 U.S.C. § 221 — Mandatory response (failure to respond is a misdemeanor; false answers subject to fine)
• 13 U.S.C. § 101-102 — Special statistics (defective/dependent/delinquent classes, religion — collected decennially at Secretary's discretion)
• 13 U.S.C. § 1 — Definitions ("Bureau" means Bureau of the Census; "Secretary" means Secretary of Commerce; "Respondent" means any person or organization that reported information)
• 13 U.S.C. § 2 — Bureau of the Census (established within the Department of Commerce)
• 13 U.S.C. § 21 — Director of the Census (appointed by President with Senate confirmation; chosen without regard to political party affiliation; must be professionally qualified — the non-partisan leadership mandate)
• 13 U.S.C. § 16 — Address information reviewed by states and local governments (Secretary sets rules for address data formats; states and localities may submit address data to build a national address list — the LUCA program's statutory basis)
• 13 U.S.C. § 195 — Use of sampling (Secretary must use statistical sampling when feasible, EXCEPT for the count used to determine congressional apportionment — the constitutional "actual enumeration" requirement)
• 13 U.S.C. § 196 — Special censuses (Secretary may conduct special population censuses for states, counties, or cities when the requesting government pays actual or estimated costs)
• 13 U.S.C. § 183 — Use of most recent population data (Secretary must transmit current population estimates to the President so federal agencies can use them for fund allocation formulas across states, counties, and localities)
• 13 U.S.C. § 214 — Wrongful disclosure of information (current or former employees who share protected census information face fines up to $250,000 and imprisonment up to 5 years — the criminal enforcement behind Title 13 confidentiality)
• 13 U.S.C. § 301-305 — Foreign trade statistics (Census Bureau collects import/export data from all parties; compiles and publishes monthly and annual trade statistics; criminal penalties for false export information or AES/SED fraud)
• 13 U.S.C. § 401-402 — Interagency data sharing (Census Bureau shares business data with Bureau of Economic Analysis and Bureau of Labor Statistics under written agreements for authorized statistical purposes — the legal basis for integrated economic statistics)

How It Works

The census is among the most consequential government operations in the United States. The decennial population count directly determines congressional apportionment and redistricting, and the allocation of over $2 trillion in annual federal funding. The Census Bureau also conducts dozens of ongoing surveys that produce the data underlying virtually every federal policy decision.

The Constitution requires an "actual enumeration" of the population every ten years, with Congress delegating the mechanics to the Secretary of Commerce. The census counts every person physically present in the United States on April 1 of the census year — citizens, noncitizens, and undocumented immigrants alike — with results delivered to the President by December 31 for apportionment and to states by March 31 of the following year for redistricting. Those population counts directly determine how the 435 House seats are distributed among the states, with gains and losses flowing from population shifts — which is why census accuracy is intensely political. The same data drives formulas distributing over $2 trillion in annual federal spending across Medicaid, SNAP, highway construction, Title I education funding, Section 8 housing vouchers, and hundreds of other programs; a 1% undercount in a state can cost hundreds of millions in lost federal funding over the decade. Beyond the decennial census, the Bureau runs the Economic Census every five years — covering manufacturing, retail, wholesale, services, and construction — and the Census of Governments, covering state and local finances, employment, and organization. These benchmarks are what GDP estimates and other economic indicators are built upon. Between decennial counts, the Bureau conducts the American Community Survey (ACS), sampling about 3.5 million households annually, and the Current Population Survey (CPS) jointly with the Bureau of Labor Statistics, which produces the monthly unemployment rate.

Individual census responses carry some of the strongest confidentiality protections in federal law under 13 U.S.C. § 9: responses cannot be shared with any other government agency — not the IRS, not immigration authorities, not law enforcement — for 72 years, and violations are criminal offenses carrying up to $250,000 in fines and five years imprisonment (§ 214). The Bureau now applies "differential privacy" techniques to published data, adding statistical noise that prevents re-identification even from aggregate tables. One key constraint: while the law requires the Bureau to use statistical sampling where feasible (§ 195), the population count used for congressional apportionment must be an "actual enumeration," not a sample — a prohibition rooted in constitutional language and reinforced by the Supreme Court in Department of Commerce v. U.S. House (1999). The Bureau also serves as the federal government's primary collector of international trade data (§§ 301-305), with all importers and exporters required to report through the Automated Export System (AES) and monthly trade balance figures published from that data. While Title 13 strictly protects individual respondent data, it authorizes the Bureau to share business data with the Bureau of Economic Analysis (BEA) and Bureau of Labor Statistics (BLS) under written agreements (§§ 401-402) — the legal foundation for the integrated economic statistics that underlie GDP calculations and employment data.

How It Affects You

State Variations

Implementing Regulations

• 15 CFR Part 90 — Procedure for Challenging Population Estimates: the formal process through which state and local governments may contest the Census Bureau's intercensal population estimates — the annual figures used in federal formula grant allocations between decennial censuses. Because federal programs distribute roughly $1.5 trillion annually based on population data, an undercount in a county's estimate can cost millions in foregone formula funding. Key provisions:

  • § 90.1 — Scope: the Census Bureau annually updates decennial census counts with estimates of births, deaths, and net migration; these intercensal estimates flow into federal allocation formulas for programs including Medicaid FMAP, Title I education funding, Highway Planning and Construction, and Community Development Block Grants; errors in these estimates have direct fiscal consequences for the governmental units affected
  • § 90.2 — Policy: the Census Bureau commits to providing the most accurate estimates possible and, to the extent feasible, giving governmental units the opportunity to seek review; challenges are not appeals — they are invitations to submit additional administrative evidence that may cause the Bureau to revise its methodology or data inputs
  • § 90.5 — Who may file: only the chief executive officer or highest elected official of a governmental unit (mayor, county executive, governor's representative); advocacy organizations, residents, and interest groups may not file directly; this limits the challenge process to governmental actors with access to administrative records
  • § 90.6 — When to file: within 90 days of the estimate's release; release occurs when the Census Bureau publishes the estimate on census.gov — online publication triggers the 90-day clock; there is no extension and no late-filing waiver
  • § 90.7 — Where to file: written challenge submitted to the Chief, Population Division at POP.challenge@census.gov or by physical mail; the Census Bureau publishes updated submission addresses in its Population Estimates Challenge documentation
  • § 90.8 — Evidence required: the governmental unit must submit evidence consistent with the Census Bureau's own standards — administrative records that reflect actual population change (building permit data, school enrollment statistics, utility connections, group quarters occupancy, Medicare enrollment); the key constraint is that challenges must use data the Census Bureau could actually incorporate into its methodology, not competing estimates from private sources
  • § 90.9 — Review: the Chief, Population Division reviews the evidence, works with the governmental unit to verify data quality, and resolves the challenge; if the Bureau finds the submitted evidence supports a revision, it will issue a revised estimate; revised estimates are retroactive to the reference date and flow into the formula allocation base

  The challenge process has been most actively used by fast-growing suburban counties and cities that believe their intercensal estimate lags behind actual growth — undercounting new housing developments, annexations, and recently constructed apartment complexes. The most effective challenges combine building permit data (capturing new construction units) with utility connection records (confirming occupancy). Challenges that simply assert the estimate is wrong without conforming administrative data are denied. The Census Bureau publishes an annual summary of challenge outcomes; historically, a small minority of challenges result in upward revisions.

• 15 CFR Part 50 — Special Services and Studies by the Bureau of the Census: fee-for-service programs through which the Census Bureau provides statistical services beyond its standard decennial and annual surveys. Key provisions:

  • § 50.5 — Age search and citizenship information: the Census Bureau will search historical census records to provide proof of age or citizenship for individuals who lack birth certificates or other vital records — particularly useful for people born before state vital records systems were established (pre-1940s); the standard fee is $65 for a search of one census covering one person, with a transcript of the relevant census entry; additional copies cost $2 each; a copy of the full census schedule (the enumeration sheet showing the household) costs $10 additional; these searches are frequently used for Social Security applications, passport applications, and inheritance disputes
  • § 50.10 — Special population censuses: the Census Bureau will conduct a complete enumeration of any state, county, city, or incorporated area upon request and payment of cost by the requesting government; the cost is calculated based on the estimated number of housing units and the complexity of enumeration; special censuses are most commonly requested by rapidly growing communities seeking updated population counts to support annexation, revenue-sharing eligibility, or state formula funding — because federal formula funds based on population often use decennial census data between census years, a community that has grown significantly may benefit from a current special census count
  • § 50.50 — Certification of statistical materials: the Census Bureau will certify population and housing unit counts, tabulations, maps, and published data products with an official Bureau seal; certification fees are preset by service type; certified counts are often required by state legislatures for municipal incorporation or annexation proceedings, by courts for voting rights litigation, and by agencies for formula funding appeals
  • § 50.60 — Certification for boundary updates: the Bureau certifies updated population and housing counts for governmental units reflecting boundary changes — incorporations, annexations, mergers, and deannexations — since these boundary changes affect the official population denominator for formula funding and per-capita calculations

  The age search program (§50.5) is the most individually accessed service — it allows people born in the early 20th century who lack birth certificates to use their enumeration in the decennial census as documentary proof of age and, in some cases, citizenship status. Census records from 1900–1950 are accessible after a 72-year privacy hold (records through 1950 are now public; the 1960 census becomes public in 2032). The special population census program (§50.10) is used by fast-growing suburbs and newly incorporated municipalities that want federal and state funding formulas to reflect their current population rather than decade-old census counts.

• 13 CFR Part 100 — Census address list improvement (procedures for local government review of census address lists)

Pending Legislation

• HR 8062 — Prohibits use of citizenship/nationality questions on the census. Status: Introduced.
• HR 4889 (Rep. Kiley, R-CA) — Limits states to one congressional redistricting per decennial census. Status: Introduced.

Recent Developments

The 2020 Census was conducted amid the COVID-19 pandemic, a citizenship question controversy (the question was ultimately not included after Supreme Court intervention), and significant operational disruptions. Differential privacy was introduced for the first time, generating debate about the tradeoff between privacy protection and data accuracy. Planning for the 2030 Census is underway, with the Bureau exploring administrative records, internet response, and other innovations to improve accuracy and reduce costs.

• Citizenship question renewed push (2025): The Trump administration revived efforts to add a citizenship question to the 2030 Census, citing the need for accurate data on citizen vs. non-citizen populations for congressional apportionment purposes. The administration has argued that non-citizens should be excluded from apportionment counts — a position that, if upheld, would shift House seats and Electoral College votes from high-immigration states (California, New York, Texas) to lower-immigration states. The Supreme Court has not directly addressed apportionment exclusion; challengers argue the Constitution requires counting all persons, not just citizens.
• DOGE Census Bureau cuts: DOGE reviews in 2025 targeted Census Bureau staffing and programs. The American Community Survey (ACS) — the ongoing survey that replaced the long-form Census and produces data used for federal fund distribution, congressional apportionment, and economic planning — faced proposed cuts and questions about whether it should be made voluntary. Making ACS voluntary would significantly reduce response rates and data quality. Congress has historically protected the ACS; budget fights continued through FY2026.
• Administrative records strategy for 2030: The Census Bureau has accelerated development of an administrative records-based enumeration approach for 2030, using data from IRS, SSA, DHS, and other federal agencies to reduce the cost and footprint of door-to-door enumeration. Privacy advocates have raised concerns about using immigration enforcement databases in the count. The approach could affect participation rates in immigrant communities and lead to undercounting in certain populations.
• 2020 Census differential privacy controversy: Post-2020 analyses found that the differential privacy noise injection algorithm — designed to prevent re-identification of individuals — introduced errors that affected small geographic areas, tribal lands, and communities of color disproportionately. These errors affected school district funding formulas, hospital siting decisions, and political boundaries drawn from 2020 data. The Bureau has adjusted the privacy loss parameters for future uses but the tradeoff between privacy and accuracy remains unresolved.