This example displays a map of US counties rendered as a collection of white-stroked polygons. It fetches TopoJSON data from the us-atlas CDN, converts it to GeoJSON using `topojson-client`’s `feature` function, and projects it with `geoAlbersUsaTerritories` from the `geo-albers-usa-territories` library. The map is drawn using `d3.geoPath` within a dynamic SVG container that resizes to the window, with state management driving the asynchronous data loading.