Board Thread:Lore Discussion/@comment-24590102-20140327052040/@comment-24590102-20140329105628

Found it  :^)

Northkeep, in 3e389, is a village with limited amenities (only a tavern and a "palace" or keep-tower) and abundant water features (decorative pools and fountains) throughout the village. It is situated between major mountain peaks to the northeast and west-southwest with: There are also roads converging north and, if I recall rightly, somewhere to the west.
 * a small village or farm the the south,
 * a small village or farm to the west with ponds and watercourse beyond
 * possibly a barrow in the north
 * forests in the northeast
 * wetlands in the east with a possible barrow situated there too
 * and a road running southeast through more forest.

It should be noted that many of the locations (e.g. Sungard, Neugrad, etc.) are nowhere near the locations observed in Skyrim – which renders anything we might estimate from triangulation meaningless. For all we know, Northkeep has since been renamed Morthal.

Given that all of the fast-travel villages are walled to allow separate treatment from the exterior world, Northkeep is not necessarily a walled village or castle – but the name is, however, suggestive. Following the naming logic, instead of triangulation (which does not fit with the Fourth Era Skyrim), Northkeep is suggestive of the northernmost point of somewhere which, based on the map, cannot be the northernmost point in Skyrim. Northkeep could, however, be the northernmost settlement or point of Falkreath Hold – which would place it on the crossroads at the triple-point in the borders dividing the Reach, Whiterun and Falkreath holds.

Given the extension of territory to annex these crossroads at the expense of tripling the border length around the immediate area, it would make sense that the crossroads were important enough to annex and, thus, important enough to defend. I can well imagine a minor trading post would have been situated here and, as a source of revenue in the form of tolls and taxes, it could justify the presence of a minor keep which might have once been an extension of the dragon mound structures in the vicinity of the crossroads.