Although in most of the U.S., parades and fireworks went ahead with some jitters but no problems, the day was not without violence as the Los Angeles area suffered twin heartbreaks.
At Los Angeles International Airport, a man killed two people at Israel's El Al airlines ticket counter before an El Al security guard shot him. And in the Los Angeles suburb of San Dimas, four people were killed and a dozen others were injured, when a small plane crashed into a park crowded with people celebrating the holiday.
The FBI says it has no evidence that anyone except the gunman was involved in the Los Angeles airport shooting, but terrorism has not been ruled out. The plane crash in San Dimas is believed to have been an accident.
In New York City, many talked of the tragedies in Los Angeles, and heartbreak was not far away in the wake of Sept. 11, as crowds determined not to let terrorism ruin their holiday defiantly gathered as usual along the banks of the East River to watch an enormous and trouble-free display of Independence Day pyrotechnics.
Bells chimed in memory of those who died at the World Trade Center, and special red fireworks in the shape of Valentine hearts gave New Yorkers a poignant reminder of the 2,823 lives lost in the attack on the twin towers.
"Don't let the terrorists win by having you afraid," had been New York Mayor Michael Bloomberg's advice in advance of the festivities, and most of New York took his advice - standing in the streets and singing "America the Beautiful" and other anthems as fireworks exploded above. "Enjoy the fireworks, remember those that we lost, and look forward to the future, which is why they all gave their lives," urged Bloomberg.
"It's breathtaking. It's wonderful. It's beautiful, like gold pouring from the sky," Lois Fontana, of Staten Island, said as the last fireworks sputtered out. "Take that and stick it in your hat, Mr. Bin Laden!"
Authorites guarding the airspace in New York early in the evening detected two small private planes, flying as low as 50 feet off the ground, in restricted airspace in Brooklyn and Queens. Authorities say police helicopters chased the two planes for 30 miles until the planes finally landed at Monmouth Executive Airport, in New Jersey.
Both pilots face reckless endangerment charges and could face further charges. Authorities are not linking the incident to terrorism.
In the nation's capital, security was just as tight, with two thousand police officers manning two dozen security checkpoints for the hundreds of thousands of people who gathered to watch the fireworks display on the National Mall.
"It was outstanding. A huge success," said Sgt. Scott Fear of the U.S. Park Police, whose department oversaw security at the Mall.
Though U.S. officials said they had no specific intelligence indicating a July 4 attack was planned in the United States, they took no chances. The military temporarily reactivated post-Sept. 11 combat jet patrols over Washington and New York City. Security zones were imposed at public places such as New York's Empire State Building and the Gateway Arch in St. Louis.
It was not clear to what extent terrorism concerns deterred people from attending Mall events. Prime viewing spots on the Washington Monument lawn went unclaimed as the first fireworks boomed in the sky just after 9 p.m. The Park Police say the turnout was typical considering the day's brutal heat and humidity, with temperatures in the upper 90s.
"The heat was more of a factor," he said.
Heat was the biggest problem on the Mall. About 50 people were treated for heat-related illnesses, with 18 taken to hospitals.
From sea to shining sea, patriotism rang out louder than usual.
In Ripley, West Virginia, some 8,000 people gathered to hear President Bush's address marking the nation's 226th birthday.
"The anniversary of America's independence is a day for gratitude and a day of celebration," said the president.
In Virginia, 82 people became U.S. citizens during the 40th annual Monticello Independence Day Celebration and Naturalization Ceremony.
Living in America with "all kinds of freedoms around you," people sometimes take those freedoms for granted, said "Angela's Ashes" author Frank McCourt, speaking at the Monticello event. "After the attacks, we began to think about being American in a way we never had before."
At Disney World in Orlando, Fla., 500 immigrants from 89 countries were sworn in as citizens.
"We are one nation, especially under God. And I don't believe 'under God' should be looked at by a judge so callously," immigration Judge Roberto Morena said to applause.
A federal appeals court ruled last month that the pledge's phrase "one nation under God" amounted to a government endorsement of religion, violating the separation of church and state.
In Philadelphia, Secretary of State Colin Powell called on Americans to live up to their national ideal of liberty by confronting poverty, bigotry and inequality as the nation pursues its war on terrorism.
In a message delivered outside the 18th century hall where America's founders declared independence from Britain on July 4, 1776, Powell avoided references to U.S. foreign policy and instead focused on Thomas Jefferson's vision of a democratic system designed to correct injustice.
"As Jefferson did in his time, so too must we recognize that America is not yet perfect," the first black secretary of state said after receiving the Philadelphia Liberty Medal.
On Philadelphia's Independence Mall, the nation's birthplace, the city conducted its annual "ringing" of the Liberty Bell.
"Those that attacked us, underestimated our resolve," Pennsylvania Gov. Mark Schweiker said. "No one will break this mold called America."
In Shanksville, Pa., where Flight 93 crashed on Sept. 11, a special tribute was held to the victims as part of that town's annual Fourth of July parade down Main Street.
In San Francisco, Jeffrey Orth, known to Bay area commuters as the Flag Man, walked across the Golden Gate Bridge waving an American flag for the last time - applauded with honks and flag-waving from passing cars.
"I think that sense of celebration of the American spirit will continue without my daily reminder," Orth said. "Hopefully all of America will reflect for a moment on the freedoms we enjoy and take for granted."