Data Sources
CountyFlow Data Sources
Every dataset we use, where it comes from, and how often it updates.
13 Data Layers & Their Sources
| Data Layer | Source Agency | Database | Update Frequency | Coverage |
|---|---|---|---|---|
| Demographics | U.S. Census Bureau | American Community Survey (ACS) | Annual | All 3,000+ counties |
| Public Safety | Federal Bureau of Investigation | Uniform Crime Reporting (UCR) / Crime Data Explorer | Annual | All reporting counties |
| Environmental Risk | Environmental Protection Agency | ECHO Database + AirNow | Quarterly | All EPA-monitored zones |
| Real Estate | County Assessor Offices + Zillow | Public Records + Zillow Home Value Index | Monthly | 3,000+ counties |
| Education | National Center for Education Statistics | Common Core of Data (CCD) | Annual | All public school districts |
| Economic Indicators | Bureau of Economic Analysis | Local Area Personal Income | Annual | All counties |
| Employment | Bureau of Labor Statistics | Local Area Unemployment Statistics (LAUS) | Monthly | All counties |
| Housing | U.S. Dept. of Housing and Urban Development | HUD Aggregated USPS Administrative Data | Quarterly | All metro + non-metro areas |
| Health | County Health Rankings | Robert Wood Johnson Foundation | Annual | All counties |
| School Ratings | GreatSchools + NCES | GreatSchools Rating + CCD | Annual | All rated districts |
| Cost of Living | Bureau of Economic Analysis + BLS | Regional Price Parities + CPI | Annual | All metro areas |
| Business Demographics | Census Bureau | Business Patterns (CBP) | Annual | All counties |
| Population Projections | Census Bureau + State Demographers | Population Estimates Program | Annual | All counties |
Our Methodology
CountyFlow aggregates publicly available data from U.S. federal agencies and presents it in a unified, easy-to-read format. We do not modify, cherry-pick, or interpret raw government data. Every metric displayed on CountyFlow includes a direct link to its source agency and the specific database it was drawn from. When agencies revise historical data (as the Census Bureau does annually), we update our records within 30 days of publication.
Known Data Limitations
- FBI UCR data is voluntary — not all law enforcement agencies report. We display coverage rates where available.
- ACS estimates have margins of error, particularly for small counties (population under 10,000).
- County assessor data update cycles vary by county — some update monthly, others annually.
- Environmental risk scores are based on EPA monitoring stations, which are denser in urban areas.
Explore county data
Put these data sources to work — search any U.S. county for free.