Located in the attachments as shown, west of Windhelm and just north of the world boss on the map (in the edge of the mountains leading north away from him.
Honestly, I wasn't even looking. Just wanted to see Skyrim. There was a, well, VERY easy ledge to jump to which leads out of the map. Bring a couple of soul gems and you can have a field day.
Thought you may want to know. That being said? It was fun, and I even snagged some pictures with my very photogenic steed.
Thanks for everything, y'all rock.
-Khal Samoset NA/US
The Rebel Syndicate
Samoset/Khal Samoset
Khal/Guildmaster, The Rebel Syndicate