A choropleth map of the United States displays the percentage of adults age 25 and older with a bachelor's degree or higher per county for 2010–2014, using a sequential color scale. The visualization is built with React and D3 v5, rendering counties via `geoPath` from TopoJSON data. It uses `scaleThreshold` for color binning, `scaleLinear` for the legend axis, and interactive tooltips that appear on mouse hover.