In celebration of St. Patrick's Day, I decided to determine exactly how Irish I am. To figure this out, I looked at my great-great-grandparent's generation. At this generation, I have 16 ancestors, three of which were born in Ireland. This makes me a total of 18.75% Irish. Using the same method I calculated that I am 37.5% German, and 43.75% Colonial American (by which I mean families that have been in America for at least 300 years). It is likely that some of the colonial branches of my family have Irish origins, but I consider these to be too distant to be a real connection to Ireland.
The families I trace back to Ireland are all in my mother's family -- the Sullivans. Three surnames on this side trace back to Ireland -- Sullivan, Hickey, and either Gallagher or Shields (this last family is a bit of a brick wall). These three families arrived in the St. Louis, Missouri area from Ireland between 1855 and 1875. Despite the relatively small percentage of my ancestry that is from Ireland, it is a heritage with which I closely identify, mostly because the Irish families represent the most recent immigrants in my tree.