In time, the old cemetery became full, and in 1866, more land was added to form Oakland Cemetery. The first burial in the newly incorporated cemetery was on September 2, 1867. In the same year, the large iron gates at the main entrance were added, and in 1871, plans were developed for an overseer's house and a chapel. Those buildings can be seen to the left of the primary entrance.
In 1927, the cemetery sold 14 acres of land to Westchester County during the construction of the Saw Mill River Parkway. The size of the cemetery--51 acres--has not changed since that time. The cemetery is divided roughly in half; the older part, St. John's Burial Ground, occupies one half and the newer part occupies the other half.