Will Unity eventually finish loading the game?

I have a terrain generation project set up. If I set the world size to a very high number, will the game eventually load? Or will Unity forever be stuck in that state until I force-quit?

Well…I guess it depends of the specs of your computer that runs unity . If they are high enough it might load but if they’re not, it will take ages to load and you won’t be able to move in your project if not optimised. You should check some article on terrain generation to see which cheats the devs use to generate huge worlds.
But I also think that if you’re terrain is 100% flat (And I think it will be because it’s kinda hard fill a huge terrain) then It will generate itself easier.
You should also try yourself if you can it would be a good experience.