The coverage kicks off Friday, July 3, and goes through Saturday, July 4.
ABC is marking America's 250th anniversary with 24 hours of unparalleled programming called "Disney Celebrates America."
The multi-platform broadcast, led by ABC News "World News Tonight" anchor David Muir, features coverage across all 50 states, beginning July 3 and running through July 4.
The iconic Times Square ball in New York City will descend on a date other than New Year's Eve for the first time as part of a historic Independence Day celebration marking America's 250th birthday.
The celebration will feature eight ball drops marking midnight across every U.S. time zone and inhabited territory, beginning in Guam and the Northern Mariana Islands and ending in American Samoa, according to an announcement by the organizer, America250.
The organizer said the rolling countdown is designed to unite Americans across the country during the nation's semiquincentennial celebration.
The eight ball drops are part of the inaugural Giving 4th Broadcast Benefit Show, a live special from One Times Square in New York City.
The event also launches Giving 4th, a nationwide initiative encouraging Americans to support charitable organizations and volunteer in their communities in honor of the country's 250th birthday.
The celebration begins with the first Times Square ball drop at 10 a.m. ET on July 3, marking midnight in Guam and the Northern Mariana Islands.
The traditional 11:59 p.m. ET countdown to the ball drop at midnight in New York will serve as the centerpiece of the nationwide celebration before the countdown continues through the remaining U.S. time zones and territories.
The final ball drop is scheduled for 7 a.m. ET on July 4, marking midnight in American Samoa.
"World News Tonight" anchor David Muir kicked off ABC News' celebration of America's 250th birthday by climbing up through Lady Liberty's right arm to reach the torch, standing over 300 feet in the air.
From the National Mall in Washington, D.C., to the Eiffel Tower in Paris, here's a look at preparations and festivities for the United States' 250th birthday.
Due to the extreme heat, gates will open at 7 p.m. Friday for the 8 p.m. Capitol Fourth Concert at the U.S. Capitol in Washington, D.C., police said.
The heat index -- what temperature it feels like with humidity -- was forecast to hit a scorching 113 degrees in D.C. on Friday.
"To ensure a safe concert, all guests are strongly encouraged to bring an ample supply of water," Capitol police said. "Non-glass water bottles and coolers are allowed."
In Philadelphia, the Salute to Independence Semiquincentennial Parade set for Friday has been canceled due to the dangerous heat wave, according to Philadelphia ABC station WPVI.
