This is a city-planet, covered in metropolis, though there are mines deep underground. 

Located in the Core worlds, it was part of the Corellian Trade Spine and was another location of the Galactic Senate after their victory at the Battle of Endor. 

It was so succesful, that the Starkiller Base superweapon was used to destroy the original planet, which then became a star.

(WoG canon) However, New Hosnian Prime was rebuilt near that star and restored to it's former glory. (But without the Senate building, though there IS a museum.)