Dynamic shadow in huge scenes.

Hi, I'm creating a procedural scene where the terrain is randomly created and is massive. Approximately 200 square kilometers. The Clipping Planes Far of the camera is at 100.000, although I think it could lower it to 80.000 because the fog.

But I have a problem with the shadows. If you increase the Shadow Distance, shadows are seen far away but disappear closely. If I low the Shadow Distance, close they look good but do not look afar.

I need shadows from far away for the shadow of a mountain in a valley, for example.

What should I do?