The crisp mountain air of Deer Lake, Pennsylvania, normally breathes a quiet serenity. In a wooded corner of Schuylkill County, the prevailing sounds are the rustle of trees and the soft crunch of footsteps from occasional visitors.

For nearly a decade, Deer Lake has served as a restored monument to the man who made it famous: Muhammad Ali. It was where the “Greatest of All Times” trained, reflected and prepared for some of boxing’s most historic fights.

On February 28, Mr. Ali’s former training camp will open its doors for a celebration of his enduring spirit. The annual event hosted by Hall of Fame boxing trainer Aaron Snowell, has something special to celebrate this year: the launch of the Muhammad Ali Forever Stamp.

Scheduled for release on January 15 to coincide with the birthday of Dr. Martin Luther King, the commemorative U.S. postage stamp represents the ultimate postal tribute to a man once vilified for refusing military service in the Vietnam War but later embraced as a global humanitarian.

“It’s just a beautiful thing,” Mr. Snowell told The New York Sun. “Anytime you can keep a man like Ali’s legacy going, it’s a beautiful thing. Now there will be a whole new era of people who will know about his legacy in and out of the ring.”

Lonnie Ali, the champ’s wife of nearly 30 years and the dedicated guardian of his legacy, was ecstatic to hear of the unveiling of the stamp scheduled for Thursday in Louisville, Kentucky. “Seeing Muhammad’s face on a stamp is so exciting for me because it’s another part of his legacy that is going out into the world,” she told the Associated Press. “He would be so honored to have this. Even though he’s not here with us, I know he knows it. It’s just another testament to the power of his legacy, his enduring legacy, and his values and convictions.”

According to his widow, Mr. Ali predicted this honor decades ago, sharing that the champ once said: “The only way I could be licked is if I was on a postage stamp. And I’m going to be licked a lot.”

Mr. Ali died in 2016 at the age of 74 after living with Parkinson’s disease for more than three decades. He was one of boxing’s most decorated fighters inside the ring, winning an Olympic gold medal in 1960 and the heavyweight championship three times. He also received accolades for his work for world peace, earning the United Nations Messenger of Peace Award in 1998 and the Presidential Medal of Freedom in 2005.

“Great fighters live off their legacy,” Mr. Snowell said. “Muhammad Ali is a part of history that we can’t let go.”

Twenty-two million Muhammad Ali stamps will be printed and sold in sheets of 20 for $15.60, according to the postal service website. The stamps feature a 1974, black-and-white Associated Press image of the boxer, peering into the lens with his gloves up. The sheet also has a 1976 image of Mr. Ali smiling in a pinstriped suit.

The stamps can be preordered online or purchased at post offices nationwide. Once they sell out, they won’t be reprinted. Because they’re Forever Stamps, the First-Class mail postage will always remain valid.

“It’s just one of those things that will be part of his legacy,” Lonnie Ali said. “It’s just one of those things that will be part of his legacy, and it will be one of the shining stars of his legacy, getting this stamp.”

Other U.S. postal products for purchase relating to Mr. Ali, include pocket-sized notebooks, collectible envelopes and a portfolio with details of the stamp’s design.

Mr. Ali joins several other boxers honored with commemorative stamps. They include Jack Dempsey, Joe Louis, Sugar Ray Robinson and Rocky Marciano.

Next month, Mr. Snowell will recount moments from Mr. Ali’s legendary battles in the ring, his court battles with the U.S. government to avoid fighting in the Vietnam War, the subsequent suspension of his title, and his remarkable comeback to reclaim the heavyweight championship in the “Rumble in the Jungle” where he knocked out George Foreman.

Among the highlights of Mr. Snowell’s upcoming celebration, which is free to the public, is having guests express their sentiments about Mr. Ali. “People can say their peace about the Champ,” Mr. Snowell said. “It’s a historical site that has been restored to look the way it did when Ali trained there.”

Mr. Snowell said the creation of this stamp is only going to add to the celebration. It might be small, but serves as a reminder of a fighter who proved that greatness is measured not only by victories, but the courage to stand for something larger than oneself.