Cognomen Buchannan (Buchannan 
) , globally, is a rare last name. The surname Buchannan is characteristic of Australia, where it is a rare surname, Costa Rica, and the United States. Not in comparison with a country's population, it is the most numerous in the United States, the United Kingdom, and Australia.
| VARIANT | COUNTRY |
|---|---|
| Buchannan | United Kingdom, Canada, Australia, United States, Costa Rica |
| john buchannan British poet (1810-1891) (b. 1810) |
|