On Memorial Day, with the last major war 80 years in the past, Americans may struggle to connect with those who paid the ultimate price for the country, but thanks to online resources, finding the heroes in our family trees is easier than ever.

About 234 World War II veterans die each day, with the total number expected to fall below 100,000 next year and the last of the 16 million Americans who served projected to pass away in 2043, the Department of Veterans Affairs says.

When past wartime generations went to their rewards, they took answers with them, and any documents are confined to dusty, far-flung archives. Today, those stories are available through resources like MyHeritage.com, FamilySearch.org, Fold3.com, and Ancestry.com. 

The U.S. National Archives at Archives.gov are free to search and MyHeritage is offering their collection of 83 million military documents — draft, enlistment, pension, and service records, as well as military biographies — without charge through Tuesday.

 “At MyHeritage,” their director of public relations, Sarah Vanunu, tells me, “we believe it’s our duty to preserve every family story, and that responsibility takes on added significance as we pay tribute to the brave men and women who gave their lives to safeguard our freedom.”

Ms. Vanunu shared the story of Marty Whitacre who, while rummaging through his mother’s garage, found a locker containing hundreds of letters written by his uncle, Glenn Whitacre, a radio operator and gunner on a B-24 bomber.

In decades past, the stories contained in those letters would have remained confined to that rusty trunk. Now, they’re a few clicks away. “The collection of letters found by Marty,” the director of research at MyHeritage, Roi Mandel, told me, “of the uncle who wrote from the frontline before he was killed in WWII, is a historical treasure.”

Mr. Whitacre’s discovery touched on another factor that makes uncovering lost relatives through traditional means a challenge. “For years,” Mr. Mandel said, “Marty’s family had been unable to talk about the story, too saddened by the loss to revisit it. But with MyHeritage’s help, they were able to delve into the life of a relative otherwise lost to time.”

When I interviewed Sally Mott Freeman in 2017, she described her journey to writing “The Jersey Brothers: A Missing Naval Officer in the Pacific and His Family’s Quest to Bring Him Home.” It began, she told me, with “a single, faded black and white photograph of my Uncle Barton.” He was held as a POW by Japan; her family didn’t discuss his death or know his fate.

“The bounty of online resources now available to grieving Gold Star families on a similar quest was in its early stages during my research,” Ms. Freeman said, but she returned often as the archives expanded. “It has been my honor to help individuals navigate those resources to find answers and gain the closure they have yearned for and deserve.”

Often, people accept that stories about fallen family members are forever lost in the fog of war. For my family, the fact that my grandparents’ relatives were killed in the genocide during the Greco-Turkish War made it accepted wisdom that any records had been burned.

My wife, Catherine, a professional genealogist, went to work anyway, uncovering records and stories that brought to life photos of ancestors whose stories existed in places we could never have tracked down in person.

Before that, my cousin once removed, Sergeant Petros Loizides, was known to me only by my great-aunt’s painting of him in uniform and a local playground named in his honor. Research introduced me to him as “Two-Gun Pete” — he carried both a .45 pistol and a machine gun — who died in the Battle of the Bulge, holding a position so his men could withdraw.

Stories like these are online to explore, just waiting to be discovered. If we pause from our barbecues and the beach to punch in the names of the fallen, we can put faces to the names, and better honor the true meaning of Memorial Day.