1. The first Ohio state fair was held on July 21, 1850, in Cincinnati. Initially, the fair was held annually on rotating locations, but since 1886, it has been held at the Ohio Expo Center in Columbus.

2. On July 21, 1931, the Buckeye Steel Castings Company in Columbus became the first steel foundry in the United States to install overhead cranes on its production lines. This innovation significantly increased the factory's efficiency and productivity.

3. In 1967, the Ohio Historical Society dedicated the newly restored Sherman House Museum on July 21. This house in Lancaster, Ohio, was the birthplace and childhood home of Civil War general William Tecumseh Sherman.

4. On July 21, 1984, the rock band Van Halen performed at Richfield Coliseum in Richfield, Ohio, as part of their "1984 Tour." The concert was notable for the band's elaborate staging, which featured a giant mechanical Frankenstein's monster and a massive stage built to resemble a futuristic cityscape.

5. The Great Ohio Flood of 1913 began on March 23 of that year but reached its peak on July 21, devastating many Ohio communities. The flooding was caused by heavy rain and snowmelt and resulted in at least 428 deaths, thousands of injuries, and millions of dollars in property damage.