Last name Русиа (Rusia 
, Rusya 
, Rousia 
) , in the world, is quite a rare cognomen. The cognomen Русиа is characteristic of Georgia, where it is quite a common surname, Philippines, where it is quite a rare surname, and Bulgaria, where it is a rare surname. In absolute terms, this name is the most popular in Philippines, Georgia, and Indonesia. More frequently, Русиа is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Rusia | Philippines, Tanzania, India, Georgia, Democratic Republic of the Congo |
| Rusya | Malaysia, India, United States, Russia, Indonesia |
| Rousia | Brazil, India, Greece, Algeria, United States |
| Русиа | Russia, Ukraine |