This choropleth map visualizes county-level US population estimates for 2020 using an Albers USA projection. It uses a threshold color scale with five blues to represent population ranges, and a legend with threshold labels clarifies the bins. The map is rendered as SVG using d3.geoPath, populating county paths by joining TopoJSON geometry with CSV data via FIPS codes. Data comes from the PopEst.csv file and the US.json TopoJSON topology.