1. South Dakota became a state on October 1, 1889, along with North Dakota, making it the 40th state in the United States.

2. The establishment of the Mount Rushmore National Memorial began on October 1, 1927. Sculptor Gutzon Borglum arrived on the scene and began his work on the iconic monument, which would eventually be completed in 1941.

3. On October 1, 1986, one of the world's largest underground dump trucks was unveiled at the Homestake Gold Mine near Lead, South Dakota. The truck, known as the Mark 36, was capable of carrying 100 tons and was a crucial element in the massive mining operation.

4. In 2015, the first-ever pheasant hunting season opened on October 1 in South Dakota. The state is known for its excellent hunting grounds, and the opening of the season is an annual event eagerly anticipated by hunters from all over the country.

5. On October 1, 2019, the Minuteman III missile was tested at Ellsworth Air Force Base in South Dakota. The missile is a key component of the country's nuclear defense system and is regularly tested to ensure its readiness in the event of an attack.