Quealy Place, in front of the cathedral, will be closed from 1 to 4 p.m., Rockville Centre police said, and heavy traffic is expected.
Buckley, 21, was just days from making a trip to Hawaii and a surprise home visit when he was fatally shot by an Afghan police officer on Aug. 10, one of six Marines killed that day in two encounters with Afghan officers. While assigned to the 3rd Battalion, he served as a logistics and facilities adviser. He was awarded the Purple Heart posthumously.
The wake for Buckley was Thursday and Friday at Vanella's Funeral Chapel in Oceanside.