Trolls and their leather is hard to come by, the first Troll you meet is in the Grimwall Mine for the Quest (The Abandoned Mine). This Troll is LvL 18 with no extra ads but the area is extremely dark to see in.
The second Troll i found is at the bottom of Grimwall, Same LvL as the mine but with ads that includes Sorcerers (LvL 13), Skeletons (LvL 2), and Wolves (LvL 5). I prefer having a group for this area and someone with the healing AoE "Healing Aura" (LvL 14 Healing).
Last Locations is at the bottom of East Athagos, these trolls are High LvL for the Area ( LvL38 Trolls). So have a big group or LvLed for it --SneakpeekTV (talk) 23:33, July 16, 2018 (UTC)
There is also 9 spawns of Young Trolls (LvL 18) in Roke's Dungeon.