Monaghan ancestors from Belmullet

Hi! I am looking for my ancestors that migrated here in approximately 1848.  Martin J. Monaghan, born in approximately 1825, married Nora McMenamin (likely sometime before 1843, as they had a son, Patrick Henry Monaghan in 1843).  They were from Belmullet, and settled in Minersville, Pennsylvania, likely due to the available work in the coal mines.  There, they had my 2nd great grandfather, John J. Monaghan in 1856.  I found most of this information from Patrick's obituary.  Patrick and John became fairly prominent citizens in the area, and Patrick actually won the Medal of Honor for his bravery in serving in the Union Army during the American Civil War.  I am not sure if Martin and Nora had more children before leaving for the US, but they had at least 3 other children besides John after they moved to the US.  I am a little uncertain of the parish system, but it looks like their Roman Catholic parish would have been Belmullet, and the civil parish would have been Kilcommon/Erris.  I am pretty sure they were Roman Catholic as Martin's funeral, John's marriage and funeral, as well as all of John's children were recorded in a Catholic church record in Shenandoah, Pennsylvania, and they are buried in the church graveyard.  I would really appreciate any information or guidance you could give me.  Thank you so much!