One of my ancestors is THOMAS CRAWFORD b. 1809 who states when he moves to Canada with wife Mary Martin that he was a METHODIST farmer from Aghanloo and he is found there in the 1831 Census living at the Drumaderry Homestead.........this is just a few miles north of LIMAVADY.......
I can determine from the 1853 Census that ROBERT CRAWFORD is living on that exact homestead and a WILLIAM CRAWFORD is living nearby on the Ballyhanna homestead or Townland.
These are the only two Crawford head of households really close to Limavady listed.
As we know this William had a son William JR who was born around 1846 who married Rachel Lindsey: we can presume he was born himself somewhere around 1820-1825.......
Thus he was likely a brother to my Thomas.........
and
as Robert isnt listed as a head of household in 1831: we could assume he was also a younger brother of Thomas
Now my Thomas named his first son Robert: again a clue at a connection........
Add in a Thomas marrying a Catherine Henry in the 1840s: and my Thomas is long gone.......
That he was born somewhere around the 1820s as well.........
This gives us a hint that there were probably 2 Senior Crawford men in the area........probably born around 1785-90
but both were either dead or gone by the 1831 census.............
Unless I am wrong: and the 1831 Thomas of Aghanloo isnt my fellow.......but one and the same who married Catherine Henry some 10+ years later?

Who these 2 progenitors of the early 1800s were: I cant find yet
What I do know is that in the early 1800s a good number of these Crawfords were ardent and radical Methodists and not Presbyterians.........although prior to 1800 most would be Presbyterian.
1766 we have another Thomas Crawford on the Flax Growers list living on the Ballycrum estate in Drumachose.
Because these guys are moving estates a lot: we can assume they didnt own the land they lived on but were COTTIERS.......people who lease/worked the land that others owned.
But there does seem to be this little pool of LImavady Crawfords that are a branch of their own.
Previously all we find in Limavady in 1740 is Mrs. Crawford..........widow? with sons?
I believe prior to that: around 1725 I identified a John Crawford: a Cottier: in the region living with the widow Hutchins.......but I will have to double check that information.
Hope this provides a few more bits to work with.