This choropleth map of the United States displays state-level COVID-19 case values with a green color scale, using lighter shades for lower numbers and darker greens for higher ones. The visualization loads CSV data and merges it with GeoJSON state geometries using d3.csv and d3.json, then renders paths with d3.geoPath and the d3.geoAlbersUsa projection. A d3.scaleQuantize maps numeric values to a five-color range, while states lacking data appear gray. The SVG is built with D3 v7 and styled with minimal CSS.