Make a US County Choropleth Map

Turn county-level data into a colored map in seconds. Paste FIPS codes with values, and every matching US county is shaded on a 5-class green-to-red scale with an automatic legend.

County data — FIPS and value, one per line

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How to use this tool

Prepare your data

Format your data as one FIPS code and one value per line, like 06037,10039107. Use the sample button to see the exact format.

Paste into the tool

Paste your lines into the text box. Each line is validated — bad FIPS codes or non-numeric values are flagged with the exact line number.

Read the map

Counties are colored into 5 equal-interval classes from green (low) to red (high). The legend shows each class's value range.

Inspect any county

Click any county on the map to see its FIPS code and your value for it in the side panel.

What people use this tool for

Election and demographic maps

Visualize vote shares, population, or income by county to spot regional patterns instantly.

Example: An analyst maps county population to show where a state's residents are concentrated.

Business performance by county

Shade counties by sales, stores, or customers to find strong and weak markets at a glance.

Example: A franchise maps customer counts per county to prioritize new locations.

Public health and research

Map case rates, survey results, or environmental readings across counties for reports and papers.

Example: A researcher visualizes survey response rates by county to check geographic coverage.

How it's calculated

County boundaries come from the US Census via the us-atlas TopoJSON dataset. Values are grouped into 5 equal-interval classes between your data's minimum and maximum, colored green through red. Validation checks every FIPS code (5 digits) and every value before drawing.

Related tools and resources

Look up individual counties with the county finder, enrich your map with the population lookup tool, or visualize point density with the heat map generator.

Frequently asked questions

What is a FIPS code?

FIPS codes are the US federal standard for identifying counties: 2 digits for the state plus 3 for the county, e.g. 06037 for Los Angeles County, California.

What does equal-interval classification mean?

The range between your smallest and largest value is split into 5 equal slices. It is easy to read, but if your data is skewed, most counties may land in one or two classes.

What happens to counties missing from my data?

They are shown in neutral gray so it is always clear which counties have data and which do not.

How many counties can I include?

All 3,000+ US counties are supported. Paste as many rows as you like — the tool validates each line and reports any problems.

Is my data uploaded anywhere?

No. Your CSV is parsed and rendered entirely in your browser; nothing is sent to a server.