At the time of this guide, there are 7 maps:
1. Zavian Abyss
2. Galitan
3. Sissubo
4. Nadiri Dockyards
5. Esseles
6. Yavin Prime
A 7th map was later added, however I'm not sure if this map counts towards the achievement:
7. Fostar Haven
You can see the name of the map you're playing during the loading screen.
You will most likely get this achievement while doing the other Ranked Fleet Battles achievements.