title: What is the format for Congressional Districts for reading in Tableau
body: <p>I know Tableau has mapping support for mapping congressional districts, but how do I do it? I currently have two fields in my table: [STATE] and [DISTRICT_NO].</p>
  
  <p>I created a custom field that combines the two:</p>
  
  <p>[STATE] + " " + STR([DISTRIC_NO])</p>
  
  <p>which produces strings like: CA 2, IL 1, AZ 3.</p>
  
  <p>I formatted the custom field to have a Geographic Role: Congressional District. </p>
  
  <p>What am I missing?</p>