title: Display only a single state with counties from a full US counties map
body: <p>Is it possible to display a single state from a full US counties map?</p>
  
  <p>I know I can get each states shape file and counties and create the topojson, but I'd rather work with one file if thats possible.</p>
  
  <p>For example take Mike Bostock's full US county map.
  <a href="https://bl.ocks.org/mbostock/4122298" rel="nofollow">US Counties Map</a>
  Would it be possible to show just NY from this?</p>
  
  <p>I haven't seen any examples showing that type of functionality.</p>