I'll add that information to what I have, so I can stay on track.
I found a few traces of Thomas Finley before 1785. Here are the links below. I could access them even when signed out, but if you can't get them, let me know and I will post them somewhere else.
The first time I looked at the 30 Nov 1769 advertisement for the sloop Newry going from Philadelphia to Newry, I thought it must be a return trip. But I just noticed that the other one from that year is dated 9 Oct 1769 in Charleston, SC. I don't think he could have gone from Charleston to Phila to Newry and back to Phila in 7 weeks in 1769. But maybe the Newry had come to Phila with a different captain, if they did things like that.
I was hoping Newry would be a hint to his origins in the British Isles. There are a lot of Finleys in Co. Down on the Freeholders Lists of 1796. But I didn't check on the map to see how close they were to Newry. There was an Alexander Finley in Rostrevor, which would be handy if you were sailing out of Newry, but there were no occupations on the Lists.
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9 Oct 1769, Charleston, a claim against the Diana, of which a Thomas Finley was master
https://www.newspapers.com/clip/96846934/a-claim-against-the-diana-of-which-he-w/30 Nov 1769, Philadelphia, the Newry, from Philadelphia to Newry
https://www.newspapers.com/clip/96834066/pennsylvania-gazette-philadelphia-30/1772, Philadelphia, Polly and Peggy, Philadelphia to Kingston, Jamaica
https://www.newspapers.com/clip/96833267/dunlap-and-claypooles-american-daily-ad/[there were a few more ads for him and this ship - looking for freight and cargo, I think]
1774, Charleston, advertising for stolen property
https://www.newspapers.com/clip/96847060/1774-charleston-his-property-stolen/1802, Is this Oliver going from Lisbon to Philadelphia?
https://www.newspapers.com/clip/96868468/oliver-finley-maybe-from-lisbon-to-phila/1803, Is this Oliver arriving at Liverpool?
https://www.newspapers.com/clip/96868785/1803-oliver-maybe-arrived-liverpool/1830, Charleston, Oliver P Finley, had not been a resident of the state for two years. Tried to vote.
https://www.newspapers.com/clip/96834479/charleston-mercury-8-dec-1830-page-2n/1831, Charleston, Oliver was of Alexandria when he died. I
https://www.newspapers.com/clip/96846679/oliver-was-of-alexandria-when-he-died/-------
and I could only access the OCR scans at
https://www.irishnewsarchive.com/ so I don't even know what port this man was working out of:
1768, Belfast Newsletter
June 7, 1768, Sloop Nancy, recently overhauled, Alexander Finley, Master
June 24, 1768, Alexander Finley, Master
They had the Belfast Newsletter for that era. I don't know if there was a Newry paper in 1760-1770.
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thoughts, etc.:
1799 - Thomas Finley dies. 1800 - Oliver Finley marries. Is there a cause and effect connection? Did the whole family go [back?] to London?
1800 Census of Philadelphia. Looking for a widow of Thomas Finley. - There is no female Finley as head of a household.
1810 Census of Philadelphia and District of Columbia - Oliver Finley not found.
1830 Census of Alexandria - Oliver Finley not found [now I see they had mortgaged the house and were on hard times, so that might explain it]
1831 - Oliver Finley dies. 1831 - Thomas A Finley selling slaves in Louisiana. Again, is there a cause and effect? were they Oliver's slaves? Do you have an exact date for Thomas' being in Louisiana?
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Any idea who this lady is?
1830, Alexandria DC, p 266
Elizabeth Fenley
1 male under 5
1 female under 5
1 female 10 to 14
1 female 20 to 29
1 female 40 to 49
no slaves
https://www.familysearch.org/ark:/61903/1:1:XHGB-H38and, less likely, this free black woman:
1830, Alexandria DC, p 234
Leonora Finley household
1 free black female 10 to 23
1 free black female over 55
https://www.familysearch.org/ark:/61903/1:1:XHGB-441------------
If Thomas Finley captained the ship Newry back to Newry in 1769, he could have waved at my gr gr gr grandfather as sailed up Carlingford Lough. They were in Ballintur, Co. Down, just south of Killowen Point, but within view of the water.