The Great Lakes basin was carved by retreating glaciers at the end of the last Ice Age, roughly 14,000 years ago, leaving behind the five lakes that today hold about one-fifth of the world's surface fresh water. By 1955, when this map was drawn, their shorelines and depths had been surveyed for the better part of a century by the U.S. Lake Survey — established in 1841 — working alongside Canadian charting efforts to keep pace with the shipping traffic moving through the lakes.
Muir Way georeferenced the original 1955 map and added shaded relief using modern digital elevation data, so the basin's glacially carved shoreline and surrounding terrain read with real topographic depth. It's printed flat on fine art paper; the dimensional look comes entirely from the shading, not from any raised or textured surface.
Note on legibility: due to the map's small original typeface and age, some text is faint, and labels beneath the darkest relief shading aren't legible. We recommend the largest available size, though some darker areas may still obscure fine print.