user32710: On this thread, the user asked what is the longest unintentional fork that Bitcoin had suffered. From the answers present, Bitcoin never had a >4 block fork until 2012. 
It has been 6 years though, and I wonder if there is a more up-to-date statistics on that question, and if any study has been done so far.

user85963: 11/12 March 2013 Chain Fork at block height 225,430.It's 31 blocks long.

32710: <p>On <a href="https://www.google.com.br/search?q=longest+blockchain+fork+that+has+been+site:bitcoin.stackexchange.com&amp;sa=X&amp;ved=2ahUKEwib29-WocfdAhUGhpAKHfIzCG4QrQIoBDAAegQICRAM&amp;biw=1680&amp;bih=971" rel="nofollow noreferrer">this</a> thread, the user asked what is the longest unintentional fork that Bitcoin had suffered. From the answers present, Bitcoin never had a >4 block fork until 2012. </p>

<p>It has been 6 years though, and I wonder if there is a more up-to-date statistics on that question, and if any study has been done so far.</p>
 85963: <p>11/12 March 2013 Chain Fork at block height 225,430.It's 31 blocks long.</p>
