Gitchie Manitou is a small (91 acre) nature preserve in Lyon County, in the extreme northwestern corner of Iowa just northwest of Granite, Iowa, or just southeast of Sioux Falls, South Dakota.
This natural prairie preserve is noted for its ancient Native American burial mounds and precambrian Sioux Quartzite outcroppings, which are about 1.6 billion years old.
It was formally dedicated as a geological, archaeological, historical, and biological preserve in 1969.
The smooth, pink-colored bedrock is the oldest exposed rock in the state.
Three brothers were convicted of the crime and sentenced to life imprisonment.