Scotsh Irish Mcknight of Castleblaney Monaghan Australia

I am researching the family McKnight (McNight, MacNight) who immigrated to Australia. As they are know to be Protestants I am presuming that they immigrated to Ireland from Scotland which was a common occurrence at times in Britsh history. From Ireland a lot of these Scotish immigrants immigrated further to America but my ancestors came to Australia. In Ireland the family settle i believe in Castleblaney in Monaghan. Does anyone know if there is a data base that details the people who immigrated to Ireland and where they settled in Ireland? Anyone who may know how I can find this information i would be most grateful for any tips in finding any information pertaining to this time in history.