How Big Gunz said, you can travel from Venore, Ab'dendriel or Edron to Gray Island, next keep going and when you get to the island, to the north-west is the depot, to the north is the NPC where you can sell creature products and more like Runes, Potions, selling for example: Grasshopper Legs.
If you keep going to the north after that NPC you can find insectoids, and to the north-east there are more and more!
There is a Hive to the north. (where are monstes like Spidris, Kollos, Hive Overseers, Sppidris elite, etc!
Frequently Asked Questions
Do I have to finish any quest to get there?
No, you don't. Everyone can get there and at any level.
At which level I should go there?
You should go there if you are above the level 80+, if you are less then there are chances to die.
Good luck and happy hunting