Maybe this is only of interest to me:
In the 1950s one Zacharias owned roughly 1 acre that my house is situated on (the 1 acre has since been subdivided, we have a bit north of a third of an acre net). Then he acquired a 164 foot wide tract adjacent to the north (same depth). First he sold an 85 foot wide lot on the north side of that lot leaving a 79 feet remainder. Then some time after that he sold the remainder to the same grantee but described it as 80 feet wide effectively moving the common boundary 1 foot south. The Title Company caught it in 1958 when he sold the 1 acre with our house to Gillogly, they revised the description recognizing the 1 foot southerly shift. Gillogly sold to Zachman in 1962 using the new description.
The interesting thing to me is the fence has persisted in the old alignment to this day, it is 1 foot north of the current described boundary. The tax assessor still shows the north adjoiner at 79 feet wide.
So, you are using a foot of your neighbor's land.
Maybe not, it depends upon the description that calls out 80ft.
Should it say that the parcel includes a portion of the lot you have, then 80ft would stand.
Should it only say the remainder of the lot north of your lot, then it can not include any of your lot.
We've lived in our present house for 22 years. A few months ago I was retained to survey a lot on the tier behind ours, and that required going around the block picking up all the evidence I could find. While passing by our place I dropped off a control point near our north line just for fun. When I later taped over to the fence I found it to be a few inches on our side. Close enough for me, and now I don't have to wonder about that anymore.
The Lot is a pending sale right now, it has a oversized garage building on it, no house. If they want to move the fence I'm not going to object.
GW Engineering surveyed and marked the boundary inside the fence in 1981. I agree with their survey.