According to Ancestry UK my DNA originates in Munster and I wonder if there were any Sheen's or Sheehan's in those 5 counties except Cork to be found?
John,
A quick search on RootsIreland shows that there were thousands of Sheehans baptized in Kerry from the late 1700s to the mid-1900s. I did not look at any other counties.
Are you looking for a particular family? If so, perhaps post the details you have?
Good luck.