This choropleth map visualizes the percentage of adults aged 25 and older with a bachelor's degree or higher across US counties from 2010-2014. Counties are colored using a sequential purple color scale, with gray indicating missing data. Built with React and D3 v5, it uses `d3.geoPath` to render county boundaries from a TopoJSON file and `d3.scaleThreshold` to define color bins. Hovering over a county triggers a tooltip displaying the county name, state, and percentage.