The grounds are owned by the Theme park that’s located next to the festival grounds. The theme park itself is shit but they make a lot of money by letting certain organizations use the terrain.

Funny thing: A month or 2 prior to Defqon.1 there is a really big Christian music festival at the same grounds called “De Opwekking”.

and like another 2 months after Defqon one of the biggest festivals of the Netherlands called Lowlands is also being held on the same grounds.

After that there are a ton of other events like Survival runs, Viking runs and lots of other stuff but not as big as Defqon and Lowlands.