Ground-to-ground is limited by the curvature of the earth(unless you're bouncing things off the atmosphere like with HF radio). Generally even with a repeater on a mountain nearby the best you can expect is ~100mi.
There are many spots on the Earth with longer LoS views. Here is an interesting list along with photographs people have made of them: https://beyondhorizons.eu/lines-of-sight/
The longest one with a photograph is 443km (275mi).
The longest one with a photograph is 443km (275mi).