1. In 1846, the Mormon pioneers arrived in the Salt Lake Valley, ending their trek westward from Illinois. It is now celebrated annually as Pioneer Day, a state holiday in Utah.

2. On September 23, 1901, the Uinta National Forest was established in northeastern Utah. The forest covers over 1 million acres and includes several popular recreation areas, including the High Uintas Wilderness.

3. On September 23, 1922, the Bureau of Reclamation began construction on the Jordan Narrows Dam in Salt Lake County. The dam, completed in 1924, created the Jordan Narrows Reservoir, which served as a primary water source for the Salt Lake Valley until the 1950s.

4. In 1949, the University of Utah unveiled its first computer, which was named the "Atanasoff-Berry Computer" after its creators. The machine was one of the earliest electronic computers and was used for scientific research and data analysis.

5. On September 23, 1991, the Utah State Capitol building was rededicated after a major renovation. The project, which took nearly a decade to complete, restored the historic building to its original splendor and added modern amenities and technology.