The Jeffers Petroglyphs site is an outcrop in southwestern Minnesota with pre-contact Native American petroglyphs. The petroglyphs are pecked into rock of the Red Rock Ridge, a 23mi-long Sioux quartzite outcrop that extends from Watonwan County, Minnesota to Brown County, Minnesota. The exposed surface is approximately 150by and surrounded by virgin prairie. Several old wagon trail ruts traverse the site, one of which is believed to be the old stage coach route from New Ulm, Minnesota to Sioux Falls, South Dakota.The exact age of the petroglyphs is not known, but the earliest petroglyphs are estimated to be from 9000 to 7000 years ago (7000 to 5000 BCE). but some atlatl symbols at Jeffers are a close match with similar symbols at Indian Knoll in Kentucky, which have been dated to 3000 BCE during the Late Archaic Period. Another clue to the age comes from the projectile point carvings, which show a projectile point design used by hunters in the Late Archaic Period. Other carvings, such as thunderbirds, dragonflies, turtles, and shamans, are symbolic of later tribes such as the Otoe tribe, Sioux, and Iowa tribe. These are believed to date between 900 CE and 1750 CE. There are over 4000 American Indian images preserved in the bedrock. The bedrock was flattened and smoothed over by glaciers 14000 years ago.
