U.S. Land TopoJSON by mbostock

This map demonstrates the TopoJSON us-atlas. The same TopoJSON file can also be used to show counties and states.

index.html

<!DOCTYPE html>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script>

var svg = d3.select("svg");

var path = d3.geoPath();

d3.json("https://d3js.org/us-10m.v1.json", function(error, us) {
  if (error) throw error;

  svg.append("path")
      .attr("d", path(topojson.feature(us, us.objects.nation)));
});

</script>