There is a story in my family (grandmother's maiden name - Kelly) that we are descended from a group of brothers from Ireland named Kelly. They came over in the late 1700's, after the Revolutionary War. The story goes that the brothers left Ireland after a failed rebellion that they were part of, so there was a price on their heads. To keep from being found by the British, the brothers all separated, one getting off at every port their ship stopped at in the US, and they never contacted each other again. Is there anyone else who has a similar story or might know anything about the truth to this? This story was told to me by my grandmother and mother when I was young and it's always stuck with me, and now that I'm grown I want to know if it's actually true.

Finding the truth may be really hard, as Kelly is such a common name. I had a family story told to me by my Aunt in Washington state, and later heard a similar story by someone in Toronto (they had never met each other). So the story was passed on, but later found out not to be true.
Unfortunately, you may have to just search backwards, starting with your Grandmother and her parents. Start by finding your Grandmother in the census, you can search at www.familysearch.org for free. If you need help knowing how to start, someone here can help.