Arlington's director, Kathryn Condon, said Thursday's service was the ideal way to dedicate the new court.
"I can't think of a better way to dedicate this hallowed ground than by honoring these forgotten heroes who until now did not have a resting place befitting their service and sacrifice," she said.
The new court's size — more than 2 acres — and design allow it to hold nearly twice as many remains as the next largest court. Remains are placed in niches several cubic feet in size.
As Arlington faces increasing pressures on its capacity, the columbarium has gone a long way toward extending the cemetery's life. About 68 percent of interments at Arlington now are cremations, cemetery officials said, a reflection of an increasing use of cremation nationally as well as Arlington policies that make more service members eligible for inurnment than ground burial.
Cemetery spokeswoman Jennifer Lynch said that without the new court, the cemetery would have run out of space for cremated remains in 2016.
The $15.6 million project, overseen by the Norfolk district of the Army Corps of Engineers, came in on time and under budget, said Peter Reilly, the Corps' project manager for Arlington.
The marble niche covers installed Thursday included each service member's name, rank, year of birth and death and the words: "You are not forgotten."