I am a Sheehan descended from a James M. Sheehan of Limerick who apparently came through Prince Edward Island around 1900 then settled and married in the Boston area.(Lowell, Malden, Billerica.)I don't know what part of Limerick he was from, nor what the "M." stands for.
I was given by my father, Edward, the middle name "Darach" which appears to possibly relate to the "Darrach" family.My father's siblings were Paul Raymond Sheehan (killed at age 22 in the Battle of Tokyo, 1945), Walter, and Glenna, recently deceased.His mother was Mary Alice McCormick, allegedly a cousin of the late Speaker of the House.My father's middle name was Stephen or Sean, depending on his alcohol content.(He was devoted to Sinn Fein).Any of these given names may have come from relatives.
I don't know whether he migrated to PEI alone or with family, and whether it was paternal or maternal family.Does any of this suggest any connections to you?