This interactive map of New York State highlights four counties (St. Lawrence, Chemung, Ulster, and Albany) in steel blue based on data from a CSV file. The visualization embeds an SVG map, using D3 v3 with queue.js to load and style the counties. Hovering over any county displays a tooltip with its name and changes the fill color, while clicks can select a county. The code implements these effects using D3's selection and event handlers, transitioning between CSS classes like `.highlight`, `.hover`, and `.active`.