Thomas Jackson Oakley Rhinelander (June 5, 1858 – July 25, 1946) was an American heir and real estate magnate who was prominent in New York Society during the Gilded Age.

[8][9] His maternal grandparents were U.S. Representative and Chief Justice of the Superior Court in New York, Thomas Jackson Oakley and Matilda (née Cruger) Oakley (the daughter of Henry Cruger, who had the unique distinction of serving as both a member of Parliament and as a New York State Senator).

[16] Two years later, he graduated from Columbia Law School in 1880, was admitted to the bar in 1881,[2] and began working for the family helping to manage their vast real estate holdings.

[12] He was elected a director and served as president of the Rhinelander Real Estate Company,[18] one of the largest landholders in New York City,[19] rivaling the Astor, Goelet, and Stuyvesant families.

[23] In 1884, T.J. and his brother Philip purchased the ancient castle of Schönburg in Oberwesel on the Rhine river in Germany, where his famous emigrant ancestor was born.

[3] Rhinelander restored the castle, which poet Ferdinand Freiligrath called "the most beautiful retreat on the Rhine," between 1885 and 1920.