When terrorists hijacked commercial airliners on that day, 2,750 people were killed in New York.
184 people died at the Pentagon, and 40 people died in Pennsylvania.
Gov. Mike DeWine says all U.S. and Ohio flags should be flown at half-staff on all public buildings and grounds throughout the state.
The order is in effect from sunrise to sunset.
Gov. DeWine is also asking Ohioans to observe a moment of silence beginning at 8:46 a.m.
That’s the time American Airlines Flight 11 hit the North Tower of the World Trade Center.