What was the first published map for an adventure?

Question

What is the first officially published dungeon map from D&D?

I believe there was no dungeon map in the first published book, but I'd like to know what the first map was that was published.

Answer 1

1974 in The Underworld and Wilderness Adventures

While the 1975 Blackmoor supplement had an actual adventure with a keyed map and a story line, the first published dungeon map can be found a year earlier in The Underworld and Wilderness Adventures, published in 1974. On page 3 is a sample cross section of multiple dungeon levels and the ways they can be linked. On page 4 is sample dungeon level map, and a key for eight numbered encounter areas is on page 5. Since the map has a key with encounters, it is technically a playable dungeon adventure, even though there's no real story around it and the main idea is to demonstrate how to lay out a dungeon level and give ideas for tricks and traps.

The Underworld and Wilderness Adventures was one of the three books in the original D&D boxed set, the earliest D&D product. You won’t find any D&D maps published earlier than this.

Answer 2

The oldest map I've been able to locate is from Dungeons & Dragons Supplement II: Blackmoor, which contains maps of the original version of the Temple of the Frog. It's DriveThruRPG listing states it was originally printed "around April 1975"

A scan of the map from a later printing can be seen in this store listing.