This choropleth maps poverty rates across U.S. counties using a red sequential color scale, with tooltips displaying the county name and exact poverty value on hover. The visualization employs d3.csv to load poverty data keyed by FIPS codes, d3.json to fetch TopoJSON boundaries, and d3.geoPath to render county shapes as SVG paths. A d3.scaleThreshold with seven bins assigns colors from d3.schemeReds, while mouse events drive a custom tooltip appended to the page. The code also uses d3-legend implicitly via script inclusion, though no legend is explicitly drawn.