Last name Mcdernott (Mcdernott 
) , all over the world, is a very rare cognomen. The cognomen Mcdernott is habitual in Australia, where it is a very rare surname, the United Kingdom, where it is an extremely rare surname, and Argentina. Not in comparison with a country's population, the name is most common in the United States, Australia, and the United Kingdom.
| VARIANT | COUNTRY |
|---|---|
| Mcdernott | Australia, Argentina, United States, United Kingdom |