diff --git a/assets/countymaps/README.md b/assets/countymaps/README.md
index 3827bff..8b453c4 100644
--- a/assets/countymaps/README.md
+++ b/assets/countymaps/README.md
@@ -1 +1 @@
-Counties as a GeoJSON. From johan's world.geo.json repo.
+Counties as a GeoJSON. Found from the NWS, converted to GeoJSON with Mapshaper. Documentation: https://www.weather.gov/gis/Counties
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