I've been toying with the idea of mapping Hell for about 25 years now since when I first started DnD. The worlds I like to create are more based around my own system independent of DnD, with entirely different systems for magic and monsters and whatnot. In my worldview, your either killing demons or being eaten by them. Monsters are few (undead, demons, devils, angels, archons, and other such metaphysical bad guys and good guys) while mysticism, magic, and might are paramount. To that end I need to show what the place looks like in order for heroes to there to confront those demons on their own ground instead of just beating them back and fending them off for a while.
So here are the first maps that I've tinkered with. The first one represents the fire n brimstone of my Catholic upbringing in a regional style. The fourth one represents Dante's vision (with hierarchy notes taken from Satanic lore in gray and red letters) in a more continental style. The two in between represent compromises in trying to marry the two ideas together. While my research is, by no means, exhaustive or definitive, I have tons of notes from all sorts of places and this is the starting point with the most basic elements shown.
Since the vision in my mind is still gaussian blurred too much, I'm not sure which way I will go next. Right now I expect that most of the map will look burned and charred since this is a reflection of something opposite of earth or possibly an inner earth...something along the lines of a runaway greenhouse gas effect covering the world in deserts while the poles remain habitable. The best description I can give is the city in the movie "Constantine" but with more fire in some places, ice in other places, and void in other places (Hell is different for each of us and mine would be being forced into absolute nothingness and stasis while listening to spin doctors try to brainwash me). I digress. I'm not sure if I want Hell to be someone's magical mansion where time and space are infinite where the journey is made within one's own mind or does it really have a geography? I dunno, still thinking on that, but the latter makes for a more interesting map.
Oh well, into the abyss I go, angelic sword in hand, to do righteous battle upon the fell hordes of the underworld and chastise them for scourging me with having such lofty visions and limited talent.
BTW, anyone else wanna come along, cut up a few demons, have a laugh or two? My stamina isn't what it used to be In the end it'll be an exercise in creative thinking, for me, at least, if for no one else and probably to my embarassment, but c'est la vie.