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The M on Platte Mound, about four miles north-east of Platteville, Wisconsin, is a hillside letter of whitewashed limestone, 241 feet high and 214 feet wide. Mining students completed it in 1937, and the University of Wisconsin-Platteville calls it the world's largest M.
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World's Largest M
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42.76354° N, 90.40677° W
FIELD GUIDE
The story
Platteville's M is a mining-school boast written across a hillside. According to the University of Wisconsin-Platteville, Wisconsin Mining School students first stamped a large M in snow on Platte Mound in 1936, then decided the following spring to build one in stone, larger than the 200-foot M of the Colorado School of Mines. WMTV15 reported in 2025 that the idea came from an M the students had seen in Colorado.
With permission from the landowner, the students used picks, crowbars and wheelbarrows to move an estimated 400 tons of limestone, finishing in May 1937. The university gives the letter as 241 feet high and 214 feet wide, built on a 45-degree slope, and says it has been cemented, limed and whitewashed over the years. The university says it was first lit on 16 October 1937, after a torch relay from campus, and that its outline is lit each fall and on special occasions with cans of kerosene.
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WHAT TO EXPECT
Free to visit, according to Travel Wisconsin. A staircase beside the M climbs the mound with views over Wisconsin, Iowa and Illinois (WMTV15 says 290 steps; Travel Wisconsin 280). Each autumn at Homecoming, students light the M with kerosene cans, and student volunteers whitewash it.
ACCESS
On Platte Mound at West Mound Road, about four miles north-east of Platteville, Wisconsin, on university-owned land (Clausen Park). WMTV15 reported in 2025 that thousands glimpse the M from Highway 151.
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