united-states
Is it legally required for districts to be contiguous?
<p>I was reading about <a href="https://en.wikipedia.org/wiki/Shaw_v._Reno" rel="noreferrer">Shaw v. Reno</a>, a case about a congressional district that was altered on the basis of the race of its voters.</p>

<p>Is there a law (precedent or statutory) which requires congressional districts to be contiguous? I was thinking that you could gerrymander much more effectively if you could make up a district from multiple unconnected parts.</p>

<p>The oddly shaped district in question:</p>

<p><a href="https://i.stack.imgur.com/5Uc7m.gif" rel="noreferrer"><img src="https://i.stack.imgur.com/5Uc7m.gif" alt="NC&#39;s twelfth district"></a></p>

<p>No; only 23 states <em>require</em> their congressional districts to be contiguous.</p>

<p>See <a href="https://books.google.com/books?id=VYICdjpivIQC&amp;lpg=PA24&amp;ots=lti9Hoc9xm&amp;dq=%2223%20states%22%20contiguous%20district&amp;pg=PA24#v=onepage&amp;q&amp;f=false"><em>Reapportionment and Redistricting in the West</em> by Gary F. Moncrief</a>:</p>

<blockquote>
  <p>Only 23 states have [contiguity] requirements for their congressional districts, although as a practical matter most congressional districts will be contiguous; the relative dearth of legal limits is a manifestation of the fact that few states have provided any express legal constraints on congressional districting at all.</p>
</blockquote>

<p>But that's not to say more states don't have contiguous districts. On <a href="http://redistricting.lls.edu/where-state.php#contiguity">Profesor Justin Levitt's website</a>, he observes that:</p>

<blockquote>
  <p>Many states require contiguity only "to the extent possible," and
  courts generally accept anomalies that otherwise seem reasonable in
  context.</p>
</blockquote>

<p>I am having a difficult time finding a list of states with such requirements; I will update if I find it.</p>
