It's certainly possible that there's a fuse without an associated circuit attached. Perhaps at one time there was a barn or garage that no longer exists?

Hmm, well it's an old house and had more than one owner in the past. There certainly was no barn here since I'm in the city, but there has been some additions to the panel recently. I can see new additions were made due to an Air Conditioner install, also the main panel looks up-side down, I wonder if it was removed and then re-installed that way not too long ago to make things fit better for the extra AC boxes that were hooked up.

The plot seems to thicken though because I have a couple kitchen receptacles that don't turn off when I remove the fuses. I also seem to have another somewhere that never loses power. I probably missed something but I've done a double-check through the panel and have spent hours trying to track this down. I'm going to take a break probably until tomorrow or so before I try to one-by-one go through the hole panel all over AGAIN to track down why I cant cut off power to those outlets.

Pull the main fuse, and make sure the receptacles all lose power. It's unlikely, but very scary to think that you may have circuits without any over-current device. Any chance that there's a subpanel around supplying additional circuits?

Hmm, there is a new grey box with two 30A breakers. No labels so I'm not so sure what it is for, but I guess I'm too worried at this time to do more probing around for the day, haha.

If you are comfortable in doing so, cut off the main switch then remove the front cover of the box. Look to see if a wire is actually attached to the screw for that fuse. This mystery fuse may have just have been a spare circuit with nothing attached to it and someone may have just screwed a fuse into the empty socket. If there is something attached to it and the ceiling is open such as in a basement, try and follow the cable. Another possibility is that it is for the motor on the oil burner which usually is a dedicated circuit even in older houses but one that you wouldnt necessarily think of while looking for outlets and lights upstairs.

If you have to come to a message board to figure out what fuse controls what you should not be fiddling around within a 20 foot radius of any fuse box.

How can we possibly tell what your fuses are controlling?

Probably your neighbor is stealing power from you. Pull the fuse and watch your neighbors house.

Good luck and post when you have someone figure it out.

I only posted because I was wondering if I had missed the obvious, such as a furnace issue, or other.

I have had the fuse removed ever since, hoping I"d stumble into something that does not work, and have an Ahah moment. But seems everything is still working as intended.

I had a fuse that went to an unused transformer, maybe for the last generation doorbells.
Casey