Anti-Apparition Charm

The Anti-Apparition Charm is a spell that prevents people from Apparating into an area.

It was cast on Hogwarts School of Witchcraft and Wizardry long ago and can be lifted by the Headmaster of the time.

Behind the scenes
Another spell exists, Anti-Disapparition Jinx, which is a spell of the same kind but prevents people from Apparating out from an area.

Appearances

 * Pottermore