Mark Cullen of Canada has created a great site with the history of his family who went from County Cavan, Ireland to Quebec: http://www.cullenancestry.ca
In Mark's words: "
John Cullen of Killinkere area and Elizabeth Carolan, daughter of Simon Carolan and Catherine Clarke of Doon, emigrated in 1826 to Bytown, Upper Canada and resettled to Templeton Township with their children Mary, Anthony, Michael, Bernard, Elizabeth, Catherine and John. They became important farmers and squared timber operators and leaders in church and community affairs and local politics."
This is of interest beyond Mark's own family--many Irish first emigrated to Canada before moving to the US (and of course some stayed in Canada). And eastern Cavan was home to a large cluster of Cullens, as my maps below show.
Mark has a comment submission form on his website.