This interactive map of New York State counties visualizes housing market data, allowing users to toggle between median home prices and the number of sales for 2022, 2023, and 2024. The map uses D3’s `geoMercator` projection and `geoPath` to render county boundaries, with a `scaleSequential` color scale providing the legend. By clicking up to five counties, a sidebar table offers detailed year-over-year comparisons. The React frontend manages user selections, while D3 builds the SVG chart, controls, and tooltips.