I just finished mapping every light and electrical outlet in our house. I made a map of the entire house and marked every light and outlet on the map. I have everything (I think) accounted for, however there is still a single 15 amp breaker on the panel that doesn't seem to correspond to any outlets/lights. I flipped it off, and I can't find anywhere in the house that loses power.
Could there be simply an unused breaker in the panel? If it's unused, why wouldn't the electrician just leave the blank piece of metal there instead?