For higher-res maps with amazing detailed analysis, I recommend Zone 0.
The following level maps were all created from ROMs of the game concerned by "Stealth" for the now-defunct website ssrg.emulationzone.org. As they are no longer easily available elsewhere online I felt it would be worthwhile putting them online myself.
Note that these maps do not include anything more than the "hard" level structure: things like springs, collapsible scenery, badniks, rings and floating or moving platforms are completely missing. This makes using these maps to plan your route more difficult than it could be. Note also that since the level appearance can change when you e.g. go inside the tree in Angel Island 1, these different images are sometimes found off to the side somewhere where they can look pretty silly. You may have to mentally reconstruct the images yourself.
Sonic The Hedgehog 2
- Emerald Hill Zone: Act 1 / Act 2
- Chemical Plant Zone: Act 1 / Act 2
- Aquatic Ruin Zone: Act 1 / Act 2
- Casino Night Zone: Act 1 / Act 2
- Hill Top Zone: Act 1 / Act 2
- Mystic Cave Zone: Act 1 / Act 2
- Oil Ocean Zone: Act 1 / Act 2
- Metropolis Zone: Act 1 / Act 2 / Act 3
- Sky Chase Zone: no map. It's not like there IS anything to map on this level anyway.
- Wing Fortress Zone: Act 1 - this map is by WKSchraff unlike the rest of the maps, which are by Stealth. It is also FULL SIZE instead of zoomed out. If anybody wants to provide similar maps for the rest of the levels then please do
- Death Egg Zone: Act 1
Sonic The Hedgehog 3
- Angel Island Zone: Act 1 / Act 2
- Hydrocity Zone: Act 1 / Act 2
- Marble Garden Zone: Act 1 / Act 2
- Carnival Night Zone: Act 1 / Act 2
- Ice Cap Zone: Act 1 / Act 2
- Launch Base Zone: Act 1 / Act 2