A friend lives in a cabin on the family farm. Built in mid 1600s according to him. It has a loft accessible by walking up (I don't know proper term) "logs" sticking out of the back wall, no railing. Step tops are flat (hewn?).
It's near Concord, Va.
It'd be interesting if he could really nail that down with some legitimate paperwork, or other evidence, as that would be crazy-old for anything in the USA. Think about it, the first permanent settlement (Jamestown) didn't begin until 1607, and really took a good ten years until you could call that a "village", eg. 1615. In general, the houses built back that far were not of a quality that would still be standing today, as most were self-built shacks and cabins, or post and beam set on dirt, not the proper masonry construction that started appearing as more of the building trades appeared in the USA ca.1700.
I think there were only three other incorporated towns in all of Virginia, by the mid-1600's, Hopewell, Hampton, and of course Williamsburg. But as is almost always the case with these old towns, the oldest building in Williamsburg today only dates back to 1695. All of the buildings built in the first 60 years of that settlement are long gone, being crappy home-spun cabins yielding to rot, fire, and progress.
Until the early 1990's, my aunt and uncle owned the oldest heritage farm in the country, continuously operated by my family for 301 years. The oldest part of the house is a log cabin, parts of which still exist inside the interior walls of the larger brick and stone additions that followed, in a style of "adding on" that might only be common to PA. Even that one only dates back to 1692.
The area where my house sits now was first occupied by a copper mine, starting in the mid-1600's, but the oldest houses still standing today dates to only 1730. Other than a few foundation or fireplace remnants, everything built in the area prior to that was too temporary to remain 300 years later.
On the "something we don't know" theme, most people look at these old houses and think the quality of old construction was generally better than stuff built today. But we have a skewed view of old construction, as the few still standing today are the exceptional cases more often owned by wealthier families, not representative of the poor hovels in which the masses were living.