Thousands of people filtered quietly among the rows of white tombstones in Arlington National Cemetery on Saturday, placing identical pine wreaths with simple red bows at the graves of sons, cousins, parents, battlefield buddies, fraternity brothers and strangers fallen in half-a-dozen wars over the past 70 years.

There were Boy Scout troops, military units in dress uniforms and extended families in mittens and earmuffs. Many headed for familiar spots and formed somber clusters around a single tomb. Some said prayers or read out combat citations and saluted. Others wept or simply stood and stared, lost in thought.

“Every stone here has a story,” said Tim Frey, 43, a police officer from Lancaster, Pa., who came to honor Lt. Col. Mark P. Phelan, a member of his Army Reserve unit, who was killed by an explosive device in Iraq in 2004. “I’m here from a sense of duty, and to see a friend again,” he said. “Other people may not know anyone, but it’s still an honor to come here.”

More than 100,000 wreaths, loaded onto about 20 tractor-trailers, arrived after a six-day caravan from Maine for the 20th annual Wreaths Across America event, sponsored by a nonprofit group. The trucks parked at scattered spots around the vast cemetery, and hundreds of volunteers handed them to waiting visitors.

The event included formal wreath-layings at the grave of President John F. Kennedy, the Tomb of the Unknowns, and the original mast of the USS Maine, a legendary battleship sunk in 1898.

The official slogan of the organizers was “Remember, Honor and Teach,” and the wreath-bearing convoy stopped for special events in towns on the way. But for most visitors to the cemetery, it was a day of personal mourning and private reflection.

“Christmas doesn’t seem to mean what it used to mean, and we need to remember that these soldiers died so we can have the things we have,” said Jeannie Ludwig, 39, of Fairfax, who was visiting the graves of her grandparents, both veterans of World War II, and the grave of a friend who died in Iraq. “My kids are still too young to understand what these soldiers did for us, but this is a way to begin talking to them about it.”

By far, the most crowded portion of the cemetery was Section 60, where the most recent casualties of American military operations in Iraq and Afghanistan are buried.

Members of the District’s National Guard unit came to mourn Spec. Darryl Dent, 19, who died in Iraq.

The grief-stricken family of Navy Cmdr. Charles K. Springle, 52, wept and hugged at his tomb. Springle died in May 2009 when a fellow U.S. soldier opened fire at a military clinic in Baghdad. His parents, Ruth and Charles, traveled from Beaufort, N.C., for the event, and were met there by his daughter, Sarah Monday.

Members of the Pi Kappa Alpha fraternity at Virginia Tech gathered to honor 1st Lt. Jeffrey Kaylor, killed by a grenade in Iraq. One member, Jeff Dawley, 26, of Reston, paid his respects to Kaylor and then headed to visit the grave of his father, who he said had died because of exposure to the chemical defoliant Agent Orange in Vietnam.

Some mourners preferred to keep their grief private. A group of tight-lipped Special Forces officers, standing next to a friend’s tomb, politely declined to speak to a reporter. At another grave, a middle-aged man recited the obituary of a soldier decorated for valor in combat, but said he would rather not talk about him.

But for many others, Wreaths Across America served as a public ritual, a way to connect veterans and their families across wars and generations, or a form of group therapy. Gray-bearded Vietnam veterans in motorcycle jackets handed out bright red Christmas caps to Boy Scout packs and shook hands with spit-and-polish Marine officers.

Lynn Hill, 62, of Silver Spring wore a historic cavalry uniform and said his mission was to memorialize the 9th and 10th Horse cavalries of the Buffalo Soldiers, the Army unit founded in 1866 and composed of freed black slaves. He said he had attended every Wreath Day since 1992, “to honor all the dead soldiers” in American history.

Regina Barnhurst, the mother of a slain Marine from Severna Park, turned her son’s tomb into a day-long gathering place for other grieving families. The spot was next to a holly tree, where she and some friends put up a ladder and invited visitors to hang personal messages on the boughs and share coffee and doughnuts.

“I used to wonder how I would survive Christmas, but this has become a way for us to support each other,” said Barnhurst, who began weeping as she recounted how her son, Eric Herzberg, had been fatally shot by a sniper in Iraq five years ago. “You have to do something to get through the holidays,” she said with a sad smile. “For all of us, there is still such a huge hole.”