Family name Castellsague (Castellsague 
) , throughout the world, is a very rare last name. The surname Castellsague is characteristic of Spain, where it is a rare surname, and France, where it is a very rare surname. Also, Castellsague is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Castellsague | France, Spain |
| montserrat bosch castellsague ES (b. 1962) |
|