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
Harrington Lake property at Harrington Lake has been managed by the National Capital Commission. The property includes four recreational buildings; the land, which formerly consisted of cultivated fields, has reverted to secondary forest. In addition to the main cottage with its fine view over the lake, the Harrington estate includes the following structures: The lake itself and the area around it are referred to as "Lac Mousseau". The name "Harrington" is thought to be a misspelling of "Hetherington", the name of a family which settled in this area. The French name "Mousseau" comes from another early settler to the area, Louis Mousseau,