County data workflow reference
Marin County, California
Use the public county JSON as a small, reproducible input for a coding mission. A useful example is validating FIPS codes, grouping rows by state and producing a documented report that another person can run.
Identify the right place
Marin County is a county or county equivalent in California. Its five-digit FIPS code is 06041; preserve the leading zero when storing county codes as text. The Gazetteer lists 308.04 square miles of water and a representative point at 38.051367, -122.746396. That point identifies the geography; it is not a street address or a site boundary.
Open this county in Census data · Download this county as JSON
County data workflow reference checklist
- Specify the input columns, expected output and handling of missing data.
- Keep the mission limited to the approved public dataset.
- Inspect returned source, tests and execution receipts before reusing the result.
County references are sample public inputs; a page does not represent a completed customer mission or a supported government-system integration.
Sources and interpretation
Geography: 2025 U.S. Census Gazetteer. Population: Vintage 2025 estimates, July 1, 2025. County equivalents include parishes, boroughs, independent cities and planning regions. Puerto Rico population is not supplied by this population file.
Population is an estimate, not a live count. Gazetteer land and water measures describe the geographic area; they do not measure service availability, households, businesses or market demand. Match the FIPS code and source vintage when joining another dataset.
More county references in California
- Madera County
California · FIPS 06039
167,927 residents · 2025 estimate
- Mariposa County
California · FIPS 06043
16,918 residents · 2025 estimate