US National Park Service's Unigrid (1985) (opens in new tab)

My favorite thing from this (and the reason I shared it) was just seeing how evocative of modern grid based web design is of these design principles, even though they predate the WWW by many years and bootstrap etc. by two decades.

Here's a 1993 one from Yellowstone (linked through the site): https://ia601009.us.archive.org/13/items/yellowstonena199330...

The article makes a nice point about how they were actual used verse what designers were doing: "Designers too often treat folder panels in the tradition of book production. The process of unfolding is allowed to determine narrative and illustration sequence just as page turning controls book design. Folder users approach them differently, however. They open the folder quickly, ignoring the sequential staging of panels. The two resulting broadsides are fragmented, with parts often upside down and even sideways. All of this is confusing to users, and they wonder why it has happened."

I really love these maps. I collect them and friends and family send them to me. I probably have 50-100. There's a wide variety, e.g. Yosemite, Volcano National Park, New Orleans Jazz Historical Park. The brochures paint vivid pictures of each park, with a central story/theme on one side containing highlights of important features, animals and plants, and a topo map on the other. They are both practical tools when in the park and are great souvenirs when you return home.