Legend has it that in 1066, after suffering a long and terrible drought, Aztec Indians appealed to their gods for help by building and using sacrificial pyramids. In answer to their prayers, great waters soon covered the pyramids and created the beautiful lake the Indians came to call Tyranena meaning, “sparkling waters”.

Chief Black Hawk came through Lake Mills shortly before the Black Hawk War of 1832, the last stand of the Indians in the Northwest Territories. After the war, the first white settlers to the area set up camp at the waterfall between the lake and creek in 1836. They renamed the lake Rock Lake. In 1838, ten years before Wisconsin became a state, an official settlement was established with both its own sawmill and gristmill built on the shores of the lake. Its name was Lake Mills.

In the 1840s, Winnebago Indians shared their knowledge of the “stone teepees” (pyramids) in Rock Lake with the settlers. Today, the mystery of the legend is as powerful as ever.