Thank you for including another post with addition...

Thank you for including another post with additional photos of this grand mansion. The floor plans are very interesting--the enfilade of reception rooms must have been very impressive as well as the the portico along the rear facade! According to "Long Island Country Houses and their Architects, 1860-1940," the house was designed by Hunt & Hunt while the directory for the Locust Valley Historical Society includes a file with "details of the fire which destroyed" dated 12/7/1954. However, I've yet to determine the location of the estate. Have you found any additional information?

-- CDR from San Marino (formerly of New York City)