US County Choropleth Map
Turn a two-column CSV of 5-digit FIPS codes and values into a choropleth of all 3,142 US counties. Five equal-interval classes from green (low) to red (high), with a value-range legend.
Quick answer: Paste FIPS-and-value CSV to build a colored US county data map. Coverage: US focused. No account is required.
Worked examples
- Small pin map — A handful of labelled pins is usually clearer than dozens of unstyled markers. Use categories or colours only when they carry meaning.
- Shareable state — When a tool stores settings in the URL, recipients can reopen the same configuration without an account.
- Export choice — PNG is useful for presentation; GeoJSON or CSV is better when the data needs to remain editable.
Limits & appropriate use
Custom maps inherit two honest limits: the basemap's and the message's. The basemap is OpenStreetMap's current picture with its ODbL attribution ask, and its gaps — new roads, thin rural detail — travel into every export that includes tiles. The message limit is design's classic one: a map can carry one argument well, and beyond a few dozen symbols the right instrument changes to data-driven mapping with clustering and categories. Both limits are stated where they matter, because the alternative is a beautiful figure that misleads its own author.
Within those bounds the workflow is complete and durable: pins, labels, colours, tight framing, pixel-ratio PNG for the slide, GeoJSON/CSV for the record, URL-state for the living version. Escalation is gentle by design — choropleths and territory shading belong to GIS with real boundaries (the blank-map library and GeoJSON exports feed it), cartographic print production wants vector pipelines, and brand-strict design systems want tokens this tool deliberately doesn't fake.
- Data-dense maps → CSV-to-map with clustering and category colour.
- Boundary shading/choropleth → GIS with census or OSM boundaries.
- Print cartography → vector exports into a design pipeline.
Data & methodology
Map imagery derives from OpenStreetMap via OpenFreeMap (ODbL attribution applies to reused basemap images); your pins and labels live only in the share URL.
For source details, licences and model limitations, see Data Sources and Methodology.
Related tools
Category: Map Creation. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
How to use
- 1Paste your FIPS,value CSV into the box (or load the sample).
- 2Check the parsed row count and fix any flagged lines.
- 3Explore the map — click counties to inspect values.
- 4Read each color band's value range from the legend.
Frequently asked questions
What format does my data need?
Two columns per line: a 5-digit FIPS code, then a number — e.g. 06037,10039107. A header row is skipped automatically.
Where do I find FIPS codes?
The US Census Bureau publishes FIPS codes for every county. The sample button loads eight real ones so you can see the format.
How are the colors assigned?
Your values are split into five equal-interval classes. Green is the lowest fifth, red the highest. The legend shows each class's value range.
What if a county has no data?
It renders in light gray. Click any county to see its FIPS code and whether your CSV has a value for it.
Can I map percentages or dollars?
Yes — any numeric column works. Currency symbols, commas and percent signs are stripped before parsing.
Is my data uploaded anywhere?
No. Parsing and rendering happen entirely in your browser; your CSV never leaves your device.