A choropleth of U.S. states shows the number of businesses per state from a CSV dataset, colored with d3.scaleSequential and d3.interpolateBlues. It renders a TopoJSON map using d3.geoPath, with each state colored according to the count from a d3.rollup aggregation. Hovering highlights a state’s name and count in a tooltip. The visualization uses React 16.9, D3 v5, and TopoJSON, with SVG and animated transitions.