Thanx Sandra for the speedy reply. In rural Ireland way back when, a majority of the population lived as farmers in 'townships. Go to the irish rootsweb, look at the 'townships' in each of the national census in the area you have a distant relative, to see if that family name showed up.
The reason a distant relative seemingly disappears is due to being a 'debtor',shipped off to a debtor colony like Oz. OR, that relative changed names to escape the law, OR, 'pressed' into the service of yukky uk'y-land royle navy, hopefully that person jumped ship to start a new life in a distant land like South America like several of my distant ancestors were forced to do, just to survive.
Keep in mind Irish Catholics who sold their birthright to the Protestants for a bowl of soup during the many famines to hit rural Ireland. These 'soupers' as they were called escaped the wrath of devout neighbors by escaping to factories of yukky uk'y-land fed likea dog, treated worse than slaves.
Between 1700 and 1900 the actual population of Ireland went from 12 million to 4 million due to famine, being debtors, forced off their farms for a debt a small as 1 dollar, those fortunate to be able find a sponsor to enable them to migrate.
Keep in mind during U.S Civil War families were separated and forced to fight in either Northern or Southern Army. There are 1,000s of histories of Irish brother or cousin fighting Irish brother or cousin, tragically dying on the bloodiest battlefields ever fought.
Anybody tracing an Irish ancestor has to know Irish history intimately if they ever expect to make any progress. It is not an easy task, to say the least.
In the 1960s the stupidest of the stupidest, referring to yukky uk'y-land politicians, of course, decided to pass a law stating every soldier serving in yukky uk'y-land military had to be a uk'y citizen. Within 1 month of the proposal to Parliament, 2/3s of uk'y military, those with Irish roots, resigned enmasse...the most humiliating yukky uk'y-land military defeat ever recorded.
These single digit IQ mental midget UK politicians called these Irish troopies deserters, called for them to be executed, instead of realizing they made the biggest blunder in yukky uk'y-land history. Sorry excuse called the Prime Minister of that time, Wilson, did his usual ostrich maneuver by scooting off to Russia to consult with master puppeteers who control his every move, every statement he made while in office, they advised him not to go to war with Ireland, they would be sure to have the backing of the U.S army, full of Irish descendants.
Hopefully this will aid you in doing a re-think as to where your distant relatives ended up. Another point to consider. Catholic Ireland supported unmarried pregnant women whose 'pregnator' avoided his responsibility thru being imprisoned, exiled, pressed into UK military service, meant these women spent many years in hospital laundries run by the Church, or became nuns themselves. In virtually every instance, families of these impregnated unmarried women were so impoverished themselves they were the reason these women ended up in these laundries.