In some places, scaled-down ceremonies were broadcast over the internet, as shutdowns to curb the spread of the virus put a damper on what is usually a day of flag-waving parades and crowds celebrating the unofficial start of the U.S. summer.
Spots that would be bustling on a normal Memorial holiday had noticeably thinner crowds.
Perhaps half of those gathered at the Vietnam Veterans Memorial in Washington wore face coverings, recommended as one way to fight infection. Only about one in 10 did so on the boardwalk by the beach in Ocean City, New Jersey.
With casinos closed, nearby Atlantic City was quiet.
Richard Burke, who bought a balloon-popping amusement stand on the boardwalk only a few weeks before the shutdown, was asking customers to use the hand sanitizer he had provided.
"As long as we protect ourselves I think we are OK," Burke said.
All 50 states have relaxed coronavirus restrictions to some degree.
Health authorities in California, which has one of the most restrictive coronavirus containment rules in the country, announced on Monday that retail with in-store shopping and places of worship may now open.
In Fort Walton Beach, Florida, a small group of veterans in uniform gathered in Beal Memorial Cemetery to recite the names of the dead and weave flowers into a wreath in a ceremony that was streamed online. Some of the attendees shook hands with each other and few, if any, wore masks.
"Instead of parades or large memorial events, we can remember the men and women who made the ultimate sacrifice in a more private way," Colonel John Sannes, the commander of the U.S. Army's 7th Special Forces Group, told the gathering.
Inside the rotunda of the Nebraska State Capitol in Lincoln, a candle was lit and veterans took turns, two at a time, to silently stand sentry on either side of a wreath over the course of a 12-hour livestreamed ceremony.
In New York City, organizers of a usually large parade on Staten Island instead arranged to have a smaller convoy of vehicles drive the route. Governor Andrew Cuomo took part in a brief ceremony at the Intrepid Sea, Air and Space Museum aboard an aircraft carrier in New York City's Hudson River.
Republican President Donald Trump, who has been criticized for initially playing down the threat posed by the coronavirus, participated in a wreath-laying ceremony at Arlington National Cemetery. He was joined by Vice President Mike Pence, their wives, and Defense Secretary Mark Esper, among others.
Trump, who is eager to have the pandemic-stricken economy in at least somewhat better shape to bolster his chances of winning re-election in the Nov. 3 vote, did not wear a mask during his visit to the cemetery in Virginia.
Joe Biden, the prospective Democratic presidential nominee, made his first public appearance outside his Delaware home since quarantining himself 10 weeks ago. He and his wife Jill, both wearing black masks, laid a wreath of white roses at a nearby veterans memorial.
U.S. economic activity in April ground to a virtual standstill and more than 20 million Americans lost their jobs due to the lockdowns imposed in March.
Total cases in the United States of COVID-19, the disease caused by the virus, have reached more than 1.66 million, the highest in the world, and 97,971 people have died, according to a Reuters tally.