From the rolling meadows of The Gardens Cemetery in West Roxbury to the iconic ballroom of Dorchester’s Florian Hall, many throughout Boston and the Commonwealth gathered Monday to remember those killed in combat.

On the 148th Memorial Day, Massachusetts politicians, veterans, and families of slain service members participated in annual commemorations, in spite of sporadic downpours.

“It’s so important that we remember those who made the ultimate sacrifice, because we are the beneficiaries,’’ said Governor Charlie Baker, who spoke at the Cedar Grove Cemetery Memorial Day Parade, which was moved inside to Florian Hall because of rain.

At the West Roxbury ceremony, Alma Hart spoke of the loss of her son, Army Private First Class John D. Hart of Bedford, who died at age 20 in Operation Iraqi Freedom.

“I think dying in battle has been too romanticized,’’ Hart told the crowd, urging people to speak plainly of the cost of war. “My fair-haired, broad-shouldered son stood and fired his weapon to defend his buddies. When he ran out of bullets, he was shot and killed.’’

Hart called on the gathered audience to actively live out the “courage to act’’ displayed by fallen soldiers like her son.

Memorial Day was first celebrated in 1868 as “Decoration Day,’’ when a group of Union Army veterans decided to adorn the gravestones of fallen comrades in Decatur, Ill. In 1971, Congress passed the “Uniform Monday Holiday Act,’’ which moved the day from May 30 to the last Monday in the month.

Unlike Veteran’s Day in November, Memorial Day is meant specifically to honor soldiers who died in combat. At Arlington National Cemetery just outside Washington, D.C., President Obama marked his last Memorial Day in office by highlighting the need for Americans to speak up for the dead.

“For us, the living — those of us who still have a voice — it is our responsibility, or obligation, to fill that silence with our love and our support and our gratitude — and not just with our words, but with our actions,’’ Obama said, according to a transcript provided by the White House.

“A nation reveals itself not only by the people it produces, but by those it remembers,’’ he said.

During the West Roxbury service, families of slain military personnel placed a memorial wreath, a Marine regiment fired a commemorative volley, and taps was performed by a member of the Commonwealth Brass Quintet.

State Senator Michael F. Rush, a lieutenant commander in the Navy Reserve and the chairman of the Joint Committee on Veterans and Federal Affairs, also offered remarks before Alma Hart spoke.

In Milton, residents braved the rain for a service that included words from a Army Major General and State Representative Walter F. Timilty.

Later, in Dorchester, State Senator Linda Dorcena Forry joined Boston Mayor Martin J. Walsh and echoed Hart’s call to action.

“As public safety officials, it is our duty to embrace and amplify [the values of veterans]. To use our power to make sure that no veteran sacrifice, and no family’s loss, is ever forgotten. That no veteran or no Gold Star family’s needs are ever left unaddressed,’’ Walsh said. “We want Boston to lead the way for our country in honoring our veteran’s sacrifice.’’

The mayor touted recent successes in curbing chronic homelessness of veterans in Boston and the city’s new “Fallen Heroes’’ memorial in the Seaport. The state senator urged the audience to hold politicians accountable on veteran’s issues.

“Even though we are doing things for veterans, we can do better,’’ Forry said. “It’s important that we remember, but it’s also important that we take action.’’

John P. Curran, an 84-year-old Korean War veteran who served in the Navy, said he looks forward to the annual ceremonies on Memorial Day, though he does so with a heavy heart.

“These are for the men and women who didn’t come back, to let them know that they’re still remembered,’’ Curran said.

John O. Scannell, a 90-year-old Army veteran from World War II, said he has been attending Memorial Day events in Dorchester for nearly 60 years. Every year, Scannell said, he thinks about his “buddies who are gone.’’

“This is why we’re here, for our brotherhood,’’ Scannell said. He ended by quoting the oft-repeated military phrase, derived from “Recessional,’’ a Rudyard Kipling poem: “Lest we forget, they would have died in vain.’’

Astead W. Herndon can be reached at astead.herndon@globe.com. Follow him on Twitter @AsteadWH.