There are four (4) variations and possibly related spellings of the name all originating in and around the Mayobridge, Tamnaharrie locales near Warrenpoint, County Down. Some are from Carlingford across the Lough from Warrenpoint.
McAdara, McAdarra, McAdaragh and McDarra are all traceable to the early 1800's in those locations through various church and land records and other contacts I've had with descendants of McAdarra, McDarra and McAdaragh..
My goal is to find if (and how) these names are related.
If anyone is interested in the information I have or can add to
it, please contact me at my e-mail.