1. Treaty of Fort Laramie was signed in 1868:
On February 18, 1868, the Treaty of Fort Laramie was signed between the United States and the Sioux Nation. The treaty guaranteed the Black Hills to the indigenous people and provided land for the construction of roads and railroads. However, the subsequent discovery of gold in the Black Hills led to conflict and ultimately the US government's seizure of the land.

2. The Black Hills Expedition in 1874:
On February 18, 1874, General George Armstrong Custer led a scientific expedition into the Black Hills region of South Dakota. The goal of the expedition was to explore the area and gather information about the geography, geology, and potential for settlement. However, the discovery of gold during the expedition led to the exploitation and displacement of indigenous people from their lands.

3. SDSU Jackrabbit Women's and Men's Basketball teams achieve victory in 2012:
The South Dakota State University Jackrabbit Women's and Men's Basketball teams achieved a double victory on February 18, 2012, in front of a record crowd of 6,158 people. The women's team defeated their rival, the University of South Dakota Coyotes, while the men's team defeated the Western Illinois University Leathernecks.

4. The Blizzard of 1978:
On February 18, 1978, South Dakota was hit by a severe blizzard that resulted in 51 deaths and $18 million in property damage. Dubbed the "Great Blizzard of 1978," it paralyzed the entire state, with snow drifts as high as 20 feet and winds of up to 50 miles per hour. The National Guard was called in to assist in rescue and recovery operations.

5. Governor Kristi Noem's inauguration in 2019:
On February 18, 2019, Kristi Noem was inaugurated as the first female governor of South Dakota. She succeeded Dennis Daugaard as the 33rd governor of the state. Noem, a Republican and former US Representative, has since focused on issues such as improving the state's economy, strengthening the agricultural sector, and ensuring public safety.