Hillandale under Construction

The Hillandale mansion was designed by architect Grosvenor Atterbury for George Rudolf Mosle and completed in 1906.  The main mansion measured 130 feet by 45 feet and was constructed of stone, brick and steel with a tile roof. Notice the “roof tree” on the ridge placed by workmen for good luck.

The estate totaled 620 acres and straddled the border between Peapack-Gladstone and Mendham Township.

Mosle was a wealthy sugar merchant, but his company, Mosle Brothers, suffered financial losses during World War I when Germany sank many of its ships. After the war Mosle was unable to collect compensation.     In 1926, the Sisters of St. John of the Cross (who would later own Blairsden) bought the estate where they ran an orphanage.  In 1949, they expanded their operations to a high school, Mount St. John Academy, which closed in 1992.   The convent was shut down in 2008. 

Hillandale was demolished in April 2023 and the estate is now a housing development and recreational fields.

See prior post on the Demolition of Hillandale.

See Online Archive records:
Ground Level photo
Roof photo