Tama cemetery 多磨霊園 (map), is enormous. I spotted it while browsing Google Maps (below, left). It has an area of 1,280,237 square meters (cemetery area of 598,627 square meters), which is 316 acres (218 hectares) (source).
[Other sources say that the Imperial Palace is 3.4 square kilometers (source), or roughly 840 acres, or 340 hectares. This much larger measure likely includes roads and moat. The smaller measure of 280 acres is referenced in an article on the “biota” (aka plants and animals) of the palace (source). Even if the Imperial Palace is larger, we can agree that Tama Cemetery is still enormous.]