In the books it is said they call him Littlefinger because his holdings are on the smallest of the Fingers. Which one is that (since his small castle does not appear on maps)? On the maps there are four. Is the smallest Finger the second most southern Finger or the second most northern one? I can't tell.
I don't know why I'm so interested. I think it's because Westeros is usually pretty detailed and then when it comes to this there is nothing. Is that a literary technique to indicate how insignificant his holdings are and how insignificant House Baelish would be if not for Petyr?