Every known tomb in Ireland has been surveyed. We are very, very lucky here for that.

Most of the Court tombs (horned cairns as they were once known) do align N/S. However, several proper passage tombs face north too - Seahan, Baltinglass, Carrowkeel B & X (I think), Seefin to name a few.

There seems to be quite a split of orientation for Irish passage tombs with many facing in easterly and westerly directions.