This choropleth map visualizes the number of births in 2022 per county across the United States, using a green color scale to encode population data. The visualization loads CSV data from a GitHub repository and county geometry from the US-10m TopoJSON file, rendering with SVG paths via `d3.geoPath` and `topojson.feature`. Interactive tooltips display the county name and birth count on mouseover, while a `d3.legendColor` legend provides scale reference. The code relies on D3 v6, d3-legend, and topojson libraries to create the map.