Harrington Lake Diefenbaker suggested that he needed a quiet place to go fishing, not too far from Ottawa. Later that year, Harrington Lake was chosen as the site for an official country residence and the buildings were formally designated as a secure residence for Canada’s prime ministers. During the first prime ministership of Pierre Trudeau, his then-wife, Margaret, added a vegetable garden; according to Kim Campbell's autobiography "Time and Chance", the garden still provided the house with fresh produce at the time of that writing. Campbell was the only Prime Minister to have spent her entire term in office residing at Harrington
Orielton, Harrington Park knighted, "Orielton's" windows were boarded up and some parts of the estate were used for goat farming. Realignment of The Northern Road to the east in the 1970s including a new bridge over Narellan Creek east of the previous one, led to the cutting off of "Orielton's" (south-eastern-running) main drive (towards Narellan Creek). A new extension was added, making the drive a "V" shape and joining the Northern road further north, roughly in line but to the east of the main homestead and farm management complex. The subdivision of "Harrington Park" in the 1990s for urban development has visually encroached