43 CFR §2653.8-2

1. (a)Periods of occupancy. Casual or occasional use will not be considered as occupancy sufficient to make the tract applied for a primary place of residence.
2. (b)Improvements constructed on the land.
   1. (1)Must have a dwelling.
   2. (2)May include associated structures such as food cellars, drying racks, caches etc.
3. (c)Evidence of occupancy. Must have evidence of permanent or seasonal occupancy for substantial periods of time.