This example shows a choropleth map of US population density by state, built with the Leaflet JavaScript library. It colors each state according to its population density using a custom color scale and provides interactive features: hovering highlights a state and displays its name and density in an info panel, while clicking zooms in on that state. The map also includes a legend showing the density ranges and their corresponding colors. The visualization uses GeoJSON state boundaries and population data from the US Census Bureau, rendered as vector layers with Leaflet’s `L.geoJson` and `L.control` for the legend and info.