Where to find Magecap in Valheim

Magecap is found in the Mistlands of Valheim. You pick it by hand.

Where the world generator places it

The world is made of zones, 64 m on a side. For each zone the game tries to place the number below, in the biomes listed; where it can land is also limited by altitude and the lie of the ground. A number below 1 is the chance that one is placed in a zone.

Open the seed map to see the biomes of your world, then look in the ones above. See Magecap for what it makes and the console command to spawn it.