LV101 commented, "Didn't know they have their very own cemetery..."
During the history of the WTB&TS there have been several burial grounds used.
Pastor Russell is buried in Rosemont United Cemetery near Pittsburgh Pennsylvania.
"Judge" Joseph F Rutherford is buried in an unmarked grave under a garage in San Diego, California, but a faux-burial was performed in a portion of the cemetery of Woodrow United Methodist Church on Staten Island, not far from the old Watchtower farm and site of WBBR (Watchtower radio).
Then some were interred (without markers, because that would be creature worship) in other Watchtower properties as the Brooklyn org expanded northward. One was nick-named "the launching pad" by Bethelites who reasoned that their dead leaders were resurrected as invisible spirit creatures who would rule with King Jesus in heaven.
The burial sites shown above are the most recent. Note that grave markers are present. It must be OK to "worship" Knorr and Franz and others now.