County FIPS codes, names, areas, populations, centroids and density from US Census Bureau data.
payments ON MAINNET (real money) · 8 live endpoints
| Endpoint | Price | What it answers |
|---|---|---|
GET /counties-by-population | $0.02 | Rank US counties by July 2025 population estimate, nationally or within one state; largest or smallest first. |
GET /counties-in-state | $0.02 | List a state's counties or county equivalents with FIPS, population and land area; resolves FIPS, postal code or name. |
GET /county-density | $0.02 | Population density of a US county per square mile and km of land, with national and state rank and US average. |
GET /county-lookup | $0.02 | US county by 5-digit FIPS or name plus state: name, area, population, density, centroid. Census Bureau data. |
GET /county-nearest-to-point | $0.02 | Counties whose Census centroids are nearest a latitude and longitude, with great-circle distance. Not point-in-polygon. |
GET /county-search | $0.02 | Search US counties by full or partial name, optionally within one state; ranked, capped at 50. |
GET /fips-parse-and-validate | $0.02 | Split a county FIPS into state and county parts, check both exist, flag retired, legacy or zero-dropped codes. |
GET /state-summary | $0.02 | State totals from county data: county count, land and water area, population, density, largest and smallest counties. |
GET /catalog returns this list as JSON. Activity hub · uptime.
Reference data from US Census Bureau Gazetteer files and Population Estimates (US public domain), provided as is. Counties and FIPS codes change; populations are July 1 estimates, not counts, and centroids are internal points, not addresses or boundaries. Not for legal, tax, voting or eligibility decisions; verify at census.gov. Every paid response carries a disclaimer field.