This choropleth map visualizes poverty estimates for US counties in 2021, using a blue color scale to encode the percentage of the population living in poverty as classified by the USDA. The map is rendered as an SVG using the D3.js v5 library and the `d3.geoPath` projection system. County data is loaded from a CSV file, while the geographic boundaries come from a TopoJSON file, with colors assigned via `d3.scaleThreshold` and a legend positioned along the top.