This interactive map displays median home prices across New York State counties for 2022–2024, with a year selector and tooltips that include mini trend charts of price changes over time. County polygons are rendered with `d3.geoPath` and a Mercator projection, filled using a viridis sequential color scale via `scaleSequential`. The React app manages UI state, while D3 handles SVG rendering, transitions, and animations on year changes. Housing data comes from the New York State Association of REALTORS®, joined with GeoJSON county boundaries.