SimHeaven have released their popular X-World America scenery for XP12.

The package download is 7.4 GB, extracted to 13.8 GB. Announcing it in a post on their website they have said;

X-World continues for X-Plane 12 the successful and high quality sceneries for X-Plane 11 like X-Europe, X-America and so on. Objects are not set by an autogen rule, they are set  following OSM data in addition with Microsoft building footprints, which leads to a more realistic look and feel.

The free scenery can be installed here