Hi Marie,
To me that Co Cork is the only likely lead leading anywhere
from
http://titheapplotmentbooks.nationalarchives.ie/search/tab/results.jsp?surname=ferguson&firstname=&county=Cork&townland=&parish=&search=Search&sort=&pageSize=&pager.offset=10 Surname Forename Townland/Street Parish County Year
Ferguson Lory Castletownsend Castlehaven Cork 1825
Ferguson Robt Dungorman Donaghmore Cork 1833
Ferguson Robt Dungorman Donaghmore Cork 1833
Ferguson R A Drummurphy Donaghmore Cork 1833
Ferguson R Carnadore Donaghmore Cork 1833
Ferguson Hugh Ballyarrel Donaghmore Cork 1833
Ferguson Hugh Ballyarrel Donaghmore Cork 1833
Ferguson Hugh Ballyarrel Donaghmore Cork 1833
Ferguson Hugh Ballyarrel Donaghmore Cork 1833
Ferguson Ardmore Timoleague Cork 1828
Ferguson Charles Timoleague Timoleague Cork 1828
the above record which is unreliable and biased and normally just a single line journal entry with no mention of other membes of household, remains an exceptional sources of locating clues
the above shrinks to 7 good clues in 3 civil parishes
Ferguson Lory [I think this is Rory]Castletownsend Castlehaven Cork1825
Ferguson Robt Dungorman Donaghmore Cork 1833
Ferguson R A Drummurphy Donaghmore Cork 1833
Ferguson R Carnadore Donaghmore Cork 1833
Ferguson Hugh Ballyarrel Donaghmore Cork 1833
Ferguson Ardmore Timoleague Cork 1828
Ferguson CharlesTimoleague Timoleague Cork 1828
there are 50 Conway entries m but no matches for living in the same civil parishes as above! I would normally search about up to two civil parish away from one spouse
several other sources exist to follow civil but I haven’t the knowledge to do that quickly
over 20 years later GV has civil parish connection only to for Co Cork
Ferguson Samuel Toormore Kilmoe Cork
Ferguson John Arderrawinny Skull Cork
Ferguson James Chapel Street Kilmocomoge Cork
Ferguson Thomas Fermoy, King's Square,(Carrignagroghera) Fermoy Cork
Ferguson Thomas Clashadoo Durrus Cork
Ferguson James Fromreague Durrus Cork
this striking the population has moved or disappeared or emmigrated from the first three parishes
earlier the flax growers of Ireland has many in co cork but no Ferguson
many irish families have records of changing denominations regularly every other generation etc so I wouldn’t judge until found historically proveable.
after the united Irishmen period , the political suspicion of each other continued for evermore, the next reaction was from catholic families feeling victimised by the church of Ireland introducing the tithes applotment books gradually from 1823 onwards and emigrating
I cant help further
good luck