Crisis On Infinite Earths: What Does The Ending Really Mean?

5. Earth-38 Has Now Merged With Earth-1

Supergirl was the first to experience one of the major changes that this new world had to offer because, in a matter of moments, she ended up running into her bestie - the Scarlet Speedster himself. Upon doing so, the pair learned that National City, CatCo and all of Earth-38 was now part of the same earth as Earth-1 (or Prime-Earth as its now being called).

A major gear change, it's one that was almost inevitable. The moment that the multiverse came into play, the-powers-that-be began devising unique ways that The Flash could cross over with Supergirl - successfully making it happen multiple times over the past four years. However, as Supergirl was only ever on a different earth because the show began on CBS, it was always destined to move to Earth-1 when The CW took over.

No more interdimensional extrapolators for Barry and Kara! Earth-1 has a Supergirl now... which presumably means that it also has a Superman too.