This example displays a map of US counties, colored with a categorical color scale and outlined in red. It renders an SVG using a TopoJSON file from the `us-atlas` package, projecting the features with a `geoAlbersUsa` projection. The code employs d3's `geoPath` to generate the map paths and `scaleOrdinal` for coloring each county by name. Hovering turns a county yellow, and the data source is a remote JSON file loaded via d3's `json` loader.