President McAleese left Dublin this morning on an eight-day visit to three north American cities.
Mrs McAleese will visit Philadelphia, where she will be conferred with an Honorary Doctorate of Laws by Villanova University.
She will spend three days in Seattle before travelling on to Vancouver.
There, she has a full programme of official events, including meeting the Lieutenant Governor, the Speaker of the Provincial Legislature of British Columbia and the Mayor of Vancouver.
It will be her twelfth visit to the United States and her second to Canada as head of state.
She is accompanied by her husband Martin, and by junior foreign minister Michael Ahern.