This interactive map of New York State displays county boundaries, which change color on hover and can be clicked to zoom in and isolate a selected county while hiding the others. A tooltip shows the county name, and a return button restores the full map view. Built with D3 v7 and TopoJSON, it uses `d3.geoMercator`, `d3.geoPath`, and SVG elements, with county boundaries from a TopoJSON file and district data loaded from external CSV files.