US without Alaska and Hawaii

Based on https://bl.ocks.org/mbostock/4090848

<!DOCTYPE html>
<style>

.states :hover {
  fill: red;
}

.state-borders {
  fill: none;
  stroke: #fff;
  stroke-width: 0.5px;
  stroke-linejoin: round;
  stroke-linecap: round;
  pointer-events: none;
}

</style>
<svg width="1000" height="500"></svg>
<script src="https://unpkg.com/d3@4"></script>
<script src="https://unpkg.com/topojson-client@3"></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;

var neighbors = topojson.neighbors(us.objects.states.geometries);
  var areas = topojson.feature(us, us.objects.states).features;
  
  //loop by neighbors to remove Alaska and Hawaii (as they dont have neighbors)
  neighbors.forEach(function(n,i) {
    //console.log(Object.keys(n).length);
    if(Object.keys(n).length==0){
      areas.splice(i,1)
    }
  });
  
  svg.append("g")
      .attr("class", "states")
    .selectAll("path")
    .data(areas)
    .enter().append("path")
      .attr("d", path);

svg.append("path")
      .attr("class", "state-borders")
      .attr("d", path(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; })));
});

</script>

https://unpkg.com/d3@4

https://unpkg.com/topojson-client@3