Radial Treemap

Using the same technique that makes a sunburst diagram out of d3.layout.partition, here's a radial treemap from d3.layout.treemap.

<!DOCTYPE html>

<head>
  <title>County Treemap</title>
</head>
<meta charset="utf-8">
<style>

svg {
  height: 500px;
  width: 1000px;
}

</style>
<body>
<div id="viz">
<svg></svg>
</div>
</body>

d3.csv("PEP_2014_PEPANNRES_with_ann.csv", cleanCensus);

function cleanCensus(data){
  data.forEach(function (county) {
    county.name = county.label.split(", ")[0]
    county.state = county.label.split(", ")[1]
    county.pop = parseInt(county["pop2014"]);
    county.trend = county["pop2014"] - county["pop2010"] > 0 ? "growth" : "loss";
    county.leafColor = county["pop2014"] - county["pop2010"] > 0 ? "green" : "red";
    county.leafData = parseInt(county["pop2014"]);
  })

packableData = nesting(data);

treemap(packableData);
}

function nesting(data) {

nestedData = d3.nest()
    .key(function (d) {
      return d.state;
    })
    .key(function (d) {
      return d.trend
    })
    .entries(data);

return packableData = {id: "root", key: "root", values: nestedData}
}

function treemap(data) {

treemap = d3.layout.treemap();

treemap
  .size([200,200])
  .children(function(d) {return d["values"]})
  .padding(function (d) {return d["values"] ? 2 : 1})
  .value(function(d) {return d.leafData ? d.leafData : 1})

treemapData = treemap(data);

var chartG = d3.select("svg")
    .append("g")
    .attr("class", "dendrogram")
    .attr("transform", "translate(250,250)");

chartG.selectAll("path")
  .data(treemapData)
  .enter()
  .append("path")
  .attr("d", function (d) {
    var arc = d3.svg.arc()
    .innerRadius(d.y + 20)
    .outerRadius(d.y + d.dy + 20);

var angles = {startAngle: (d.x / 200) * Math.PI * 2, endAngle: ((d.x + d.dx)/200) * Math.PI * 2};
    return arc(angles)
  })
  .style("fill", function (d) {return d.leafColor ? d.leafColor : "grey"})
  .style("fill-opacity", function (d) {return d.leafColor ? 1 : .1})
  .style("stroke", function (d) {return d.leafColor ? d3.rgb(d.leafColor).darker() : "black"})

}

</script>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.16/d3.min.js