For it is Mary, Mary plain as any name can be
But with propriety, society will say ‘Marie’
But it was Mary, Mary long before the fashions came
And there is something there that sounds so square
It’s a grand old name.
Thus goes an old Broadway musical song of 1906, by George M Cohan, song-writer and son of Irish immigrants to the United States.
There were many such immigrants before, during and after the famine of the 1840s. One database, that of the Dunbrody Famine Ship, lists not one but ten Mary OLoughlins. There were several other Marys listed with variations of the Clan surname — and doubtless many more, as this database only starts from 1846.
American Clan descendants might like to take a look at the web-site of the Dunbrody, an attraction commemorating the Irish-American migration experience, in County Wexford, Ireland.