The city's longest-running observance of the Memorial Day holiday will hit the streets of Lower Mills and Cedar Grove on Monday morning, as veterans and their families join neighbors for a parade to salute the sacrifices of the neighborhood's war dead - and their comrades who returned.

The neighborhood's official observation begins with a 10 a.m. parade from Lower Mills to Cedar Grove Cemetery, where the former commander of a forward operating base at Abu Ghraib, Iraq - Colonel Bernard A. Flynn, Jr. - will be the featured speaker. Hundreds of Dorchester veterans - including many killed in action in conflicts dating to the Civil War - are interred at Cedar Grove, including Sgt. Daniel Londono, who was killed at age 24 by a roadside bomb in Iraq in March 2004.

In a break with tradition, members of the John P. McKeon Post in Neponset - which in recent years has constituted the biggest group of veterans marching in the parade - will not join the larger parade in Lower Mills. Instead, according to its spring 2008 newsletter, the McKeon Post will march directly from its post on Hilltop Street to the cemetery. They will be joined by the Greater Boston Gaelic Brigade, a pipe band. The rest of the veterans postS who participate in the main parade - which walks up Dorchester Ave. from Richmond Street to the Boston Home and then to the cemetery - will be joined by bands from Northeastern University and the Thomas Kenney Elementary School, along with other units, including the St. Mark's Boy Scouts and the Irish 28th Massachusetts Volunteers. The "host post" for this year's parade is the St. Mark's Post No. 1758 V.F.W., chaired by Frank Cahill.

"We honor those who gave up their lives to keep this country free," Cahill said. "While we live our lives and enjoy the fruits of a normal and satisfying life, they gave up that ability so very long ago. They are forever young."

Colonel Flynn, the main speaker at the cemetery ceremony, is currently the commander of the 26th Yankee Infantry Brigade Combat team. According to a biography, Flynn has served as the commander of Camp Edwards on Cape Cod and has led the 26th Military Police Company during his Army career. He was promoted to the rank of Colonel in 2002 and assigned as the chief of the National Detainee Reporting Center. In May 2005, he took command at Abu Ghraib. His awards and decorations include the Bronze Star.

Flynn was featured in a Frontline documentary, "The Torture Question", which aired on PBS in 2007 and focused on the scandal over mistreatment of detainees at the Abu Ghraib prison. Flynn took command at the facility in 2005, two years after the abuses at the prison came to light. In the documentary, Flynn discussed the precarious nature of defending the prison base.

" It's a high-visibility target because we're in a bad neighborhood," Flynn said in the documentary. "All of Iraq is a bad neighborhood. It's four walls all directions, with towers. There's one tower where it's built so close to the neighborhood that we can look into the bedrooms, you know, right there on the porches. There were snipers on those roofs and on those porches firing at the soldiers who were up there on the towers. So we're constantly on guard and trying to defend this and trying keep the insurgents away from coming inside."

A committee of local veterans' groups organizes the morning program, following in the footsteps of successive generations of vets dating back to the Civil War. The ceremonies at Cedar Grove Cemetery, believed to be the oldest in the city of Boston, typically draws a large turnout from the surrounding neighborhood.

Dorchester's modern Memorial Day observances continue a tradition begun by members of the now-defunct Benjamin Stone Grand Army of the Republic post #68 in Fields Corner in 1868. In the post Civil War days, the holiday was known as Decoration Day. The apex of the modern day Memorial Day observances in Dorchester, by most accounts, was 1958, when Sen. John F. Kennedy gave the keynote address at the Victory Road Armory.

Immediately following the observances at Cedar Grove Cemetery, veterans will gather at Dorchester Vietnam Memorial on Morrissey Boulevard for a remembrance service.