Reavey/Ward Families Gargarry 1870's

Hi!

My grandmothers family is from Gargarry, Lower Drumgooland, Down. They are R.C. and left during the 1870's, settling in Springfield, Mass.  The oldest ancestor was a William (1770-1854) Reavey who married Sarah and his son, William Reavey (1800-1879) who married Catherine O'Hare as well as Hugh Ward (c1770) who married Catherine Dorby (Dorley?) and his son, Patrick Ward (c.1800). The two families came over together and three sets of their children married. I have just a couple of queries to ask...

1.  Any idea of why people were leaving the area at that time? Was there a small famine in the area, was it religious?

2.  If they were from Gargarry and Catholic what cemetary could they possible be buried at? And, is there online access to it?

3. Is this area still a townland or is it a bit off the beaten path?  I am considering a trip out and New Castle seems the closest place to stay. Would love to know where the graveyard is so I have an idea of where to go...

Thanks so much!!

~Elissha