Melaghlin Reagh Ua Seachnasaigh (died 1179) was an Irish Chief of the Name.
Ó Seachnasaigh was the first bearer of the surname to be listed as of Cenél Áeda na hEchtge.
However, the territory seems to have been contended with the Ó Cathail family.
The Annals of the Four Masters record, sub anno 1179: Melaghlin Reagh O'Shaughnessy, Lord of half the territory of Kinelea, was killed by the son of Donough O'Cahill.
This biography of a member of an Irish royal house is a stub.