In 1974, Bill Hoyt, part of the original Blackmoor Bunch, started playing Dungeons & Dragons, which he’d got at Gary Gygax’s house. Soon after, he began his own campaign.
These are rare maps and campaign notes from the very beginning of D&D.
Note: This download is pretty hefty, because it contains large scans of the original campaign map, as well as a modern redrawing.
There is a “resized” version with only 39MB though.