In 1920 the Harold Pratt House was designed and erected for Mr. and Mrs. Harold Irving Pratt by the famous New York architect, William Adams Delano, of the firm Delano and Aldrich. The prestigious firm was sought out from the wealthiest of families including the Rockefellers, Astors, Vanderbilts and Whitneys for their coveted architectural styles. Only the best materials available were used in constructing the house which is reputed to have cost over a million dollars in 1920.

Mr. Harold Irving Pratt was the youngest of eight children. His father, Mr. Charles Pratt, merged Pratt Astral oil with John D. Rockefeller’s Standard Oil of New Jersey during the latter part of the 19th century. Mr. Harold Irving Pratt was the managing director of Charles Pratt and Co and was also a Council on Foreign Relations member from 1923 until 1939.

The house was boarded up during the Great Depression and with the Council on Foreign Relations outgrowing its original space, Mr. Hamilton Fish Armstrong telephoned Mrs. Pratt to see if she would donate her house. The next day Mrs. Pratt called to say that she would give the House to the Council. The House officially opened as the Council on Foreign Relations’ new headquarters on April 16, 1945.

The exterior of the house is limestone, custom made in the United States. The Pratt family’s dining room was on the main floor where the current Altschul Drawing Room now exists. Up the winding custom marble staircase to the second floor was the family library which also functioned as a dining room.

The current Rockefeller Mansion Ballroom was the Pratt family’s formal drawing/living room. At Mrs. Pratt’s insistence it was square, being modeled after a room she had seen in Ireland. It is decorated with pine paneling and beautiful chandeliers each of whose crystals are completely unique.

It was also Mrs. Pratt’s wish to use the hand-painted Venetian type doors for the entrance to the Library and the drawing room, although the architect demurred that they did not fit with the English architecture. These charming doors are still gracing the entrances to the Rockefeller Mansion Ballroom and Rubin Library. 

The Pratt family gave three paintings of themselves seated with the original furnishings. These are located in the marble Effron Hall and over the mantel of the Hauser Sitting room. To this day, the Council has maintained its original integrity and beauty.