from On OD&D's Setting:
The map from Avalon Hill's Outdoor Survival was the stated setting of original Dungeons & Dragons, and it's gotten a lot of love as a simple world for hexcrawling. If the hexes are 5 miles across, then it's about 175 miles by 180 miles - or 31,500 square miles, a heavily forested inland area that's around the size of South Carolina or the Czech Republic. Here is the description of this world:
"The so-called Wilderness really consists of unexplored land, cities and castles, not to mention the area immediately surrounding the castle (ruined or otherwise) which housed the dungeons."
If you actually read the wilderness description in OD&D volume 3: The Underworld & Wilderness Adventures, it turns out that the implied details of the setting are weird. Fighters in castles demand to be jousted, magic-users cast Geas and send them out after treasure, clerics demand a tithe or send the characters on a Quest.
But the real weirdness, and this was apparently confirmed in Gary Gygax's campaigns, is what is there when you start wandering about the wilderness. Mountains are haunted by cavemen and necromancers; deserts are home of nomads and dervishes. The "Optional" animal listings turns swampland into the Mesozoic Era - rather than alligators and snakes it is full of tyrannosaurs and triceratops. Arid plains are Barsoomian, with banths, thoats, calots and the lot, while mountains are outright paleolithic, peopled by mammoths, titanotheres, mastodons, and sabre-tooth cats. Gygax confirms this:
"When I was using the pre-World of Greyhawk map for my world setting, the West Coast of North America was the Pleistocene
region inhabited by savage cavemen and their contemporary fauna."
... more and more I'm finding that I like the idea of this setting. It's radically different from, say, the more comfortable World of Greyhawk, or most other fantastic realms; it's a true outland, where civilization hangs on by a thread. It leaves open terrific possibilities; the nomads, dervishes, cavemen, and berserkers all live in the world around towns; so do centaurs and pixies and minotaurs. I want to start to go into what the oddities of this setting are, and how they fit; it's a good match for the concept of "Demon-Haunted Lands," which I'm seeing more and more as a way to make something unique out of this setting.
An edited collection of essays on various aspects of the implied OD&D setting based upon the map from Avalon Hill's Outdoor Survival boardgame, which was part of the recommended additional equipment for the original Dungeons & Dragons. Essay topics include character strongholds and their relationship to the landscape, and discussions of the common terrain types and what effect terrain has on other aspects of the game.