1. The first official Mother's Day was celebrated in Iowa on May 9, 1914, after President Woodrow Wilson signed a proclamation recognizing the holiday. Anna Jarvis, who is credited with starting the tradition of Mother's Day in the United States, had lobbied for years to have the day recognized as a national holiday.

2. On May 9, 1864, Union troops under the command of General Grenville Dodge engaged in a skirmish with Confederate forces led by General Stephen D. Lee near Tishomingo Creek, Mississippi. The Battle of Tishomingo Creek was a small engagement in the larger campaign to take the strategic city of Vicksburg.

3. May 9, 1936 marked the opening of the Iowa State Fairgrounds Speedway, a half-mile dirt track located in Des Moines. The track hosted stock car and open-wheel racing events for more than six decades before it was closed in 1995. Today, a portion of the fairgrounds is still used for racing events.

4. On May 9, 1973, the Iowa House of Representatives passed a bill legalizing abortion in the state. The bill, which became known as the "Iowa Freedom of Choice Act," allowed a woman to have an abortion for any reason during the first 20 weeks of pregnancy. The law was later overturned by the Iowa Supreme Court.

5. The National Balloon Classic, one of the largest hot air balloon festivals in the United States, traditionally takes place in Iowa during the first week of August. However, on May 9, 1987, the event was held in May for the first time due to scheduling conflicts. The festival features more than 100 hot air balloons and draws thousands of spectators each year.