Gov. Sonny Perdue has ordered all flags at state buildings to fly at half-staff until sunset Thursday.
The Gwinnett County Fire Department held a moment of silence over its radio channels at 8:46 a.m.
Georgia Tech students are displaying 2,977 American flags on campus to represent each victim and survivor. The school scheduled a ceremony at 11 a.m. at the Campanile fountain.
At the University of Georgia in Athens, the Army ROTC hosted a flag raising and 5K run at 6:30 a.m.
On Sept. 11, 2001, terrorists affiliated with al-Qaida hijacked four airplanes and crashed them into the World Trade Center Towers in New York, the Pentagon in Washington, D.C. and a field in field in Pennsylvania.
In South Carolina, a bell in an old fire watch tower in Charleston tolled 343 times as firefighters paused to remember the New York firefighters who fell in the Sept. 11 terror attacks.
The Thursday ceremony was perhaps more moving as Charleston wrestles with the loss last year of nine of its own firefighters killed in a furniture store blaze.
It took about 10 minutes to ring the bell atop the tower in the historic district. The tolling began just before 10 a.m., about the time the first World Trade Center tower began falling eight years ago.
Across the harbor aboard the USS Yorktown, bagpipes played and Taps sounded during another observance.
School children then joined Mount Pleasant Mayor Harry Hallman in throwing a wreath into the harbor in honor of those who died.