English: n 1903, J.B. Duke first announced plans to erect a formal mansion on the estate. The architectural firm would have been Kendall, Taylor & Stevens of Boston, but the plans were not executed at the time.

In 1909, two years after his second marriage, Duke again contemplated building a country mansion; at the same time, he planned another in New York City. Philadelphia architect Horace Trumbauer, noted for his elegant mansions based on 17th century French Renaissance styles, was invited to submit plans for both mansions. In 1911, construction proceeded at Duke Farms on the two-level basement and service court for the mansion, including a tunnel from the approach road. But construction abruptly stopped after the foundation was laid. There are a number of theories as to why construction of the mansion was abandoned. One theory is that with the court-ordered dissolution of the American Tobacco Company monopoly in 1911, Duke shifted his capital from tobacco to hydroelectric power, and increasingly spent time in Charlotte, N.C., where he built additions to another house he had bought in 1919 called “Lynnwood.” Duke may have felt that because he was moving his capital to new ventures, it was not prudent to spend additional money on the New Jersey mansion. Duke donated the remaining materials to the U.S. war effort by 1918 and abandoned the mansion altogether.

Today, the remnants of this building project may be seen at the Old Foundation site, which overlooks the Great Meadow, a centerpiece of the habitat regeneration efforts at Duke Farms.