Cognomen Rheinallt (Rheinallt 
) , globally, is an extremely rare surname. Much more frequently, Rheinallt is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Rheinallt | United Kingdom, United States, South Africa |
| hywel ap rheinallt Welsh poet |
|
|
| maredudd ap rheinallt |
|