1. In 1838, the Treaty of 1838 was signed, in which the Sacs and Foxes ceded their lands in Iowa to the U.S. government. This opened up the territory for white settlement.

2. On May 28, 1861, Iowa Governor Samuel Kirkwood issued a call for the first volunteer regiment of soldiers to fight in the Civil War. The regiment, known as the 1st Iowa Infantry, was mustered into service on June 1st.

3. The Great Flood of 1881 began on May 28th in the town of Dubuque, Iowa. Over the course of three days, heavy rains caused the Mississippi River to rise to record levels, flooding many towns along its banks.

4. In 1934, the town of Spencer, Iowa was struck by a powerful tornado on May 28th. The tornado destroyed much of the town, causing 19 fatalities and over $1 million in damage.

5. On May 28, 1951, the Iowa State Highway Patrol was established. The agency was created to enforce traffic laws, investigate crimes on the state's highways, and assist stranded motorists. Today, the Iowa State Patrol is still active and plays an important role in keeping Iowa's roads safe.