What/where is Tamriel? Tamriel is on a planet called Nirn. It is the world where The Elder Scrolls games take place. I've only played two of the five (six, counting the MMO) games. Oblivion and Skyrim.
In Oblivion, there's an unmarked campsite way, high up in the mountains called Dive Rock. It's one of the highest points you can get to in the game, and you get to fight a large, semi-invisible Frost Troll called the Uderfrykte Matron. I say it's a Frost Troll since you find her in the snow-covered mountains. But in Oblivion there are very few special trolls, they're all just called trolls.
Anyway, it's very hard to get to Dive Rock, and you find out about it from finding a dead person at the bottom of the mountain. The dead body is north of Aerin's Camp and Dive Rock is located northwest from the dead body. But it's very tricky to get to from there, even on a horse. But I found an easier way to find it.
If you have the Wizard's Tower plugin, then once you reach the wooden bridge leading you to the tower, just turn the other way and you can run along the mountaintops until you see the marker on your compass (it will be a landmark icon). Once you reach Dive Rock, you will find a tent, a fire and a sack with some stuff in it. You'll also find a diary telling you what the author was doing there. You can choose to go find the troll and kill it or just leave it. If you go kill it, you will find the Frostwyrm Bow inside it (along with Svejna). You'll also likely run across her dead husband in the same area, where you can loot him (except for the fur helmet on the ground)
Be aware though, this is a pretty tough troll at any level. Besides being semi-invisible and hard to see, she's also fast, though clumsy if she tries to run uphill. She's still weak to fire spells, and she can't climb very well, so your best bet is to use ranged fire magic on her from the side of the mountain. That should kill her before she can reach you. You can also peg her with fire arrows, if you have them, or a fire-enchanted bow if you have one. Just try not to let it get close, that's where it's dangerous, just like any other troll.
You can also walk towards the edge of the camp a certain way, until you get a message popped up on your screen. Then you'll have several new map markers of dungeons you can visit and loot. You can also fast travel to the camp after you find it and use it for yourself. You won't have to clear out any bandits here, none ever spawn there like at regular campsites.
Anyway, that was all I wanted to muse about. I was going to put this in my Wordpress Tamriel blog, but Wordpress is acting up and won't take me to the posting page.