Despite its name, the graveyard pre-dates the adjacent King's Chapel (whose first structure was built in 1688); it is not affiliated with that or any other church.
[1] King's Chapel Burying Ground was founded in 1630 as the first graveyard in the city of Boston.
Today there are 505 headstones and 59 footstones remaining from the more than one thousand people buried in the small space since its inception.
This includes the large vault, built as a charnel house, which was converted into a tomb for children's remains in 1833.
[1] Media related to King's Chapel Burying Ground at Wikimedia Commons