This choropleth shows the number of universities per U.S. state, with darker orange shades indicating higher counts and gray for states without data. Hovering over a state reveals a tooltip with its name and university total. The visualization uses d3.geoPath with a geoAlbersUsa projection to render TopoJSON state boundaries from us-atlas, and d3.scaleSequential with an interpolateOranges color scheme to encode values. State data is provided via a hardcoded array in USA.html, while the separate usa.js version loads the same values from a CSV file.