James O'Donnell (1774–1830) was a noted Irish-American architect in New York City and Montreal.
James O’Donnell was born in County Wexford, Ireland, to a wealthy family of Anglo-Irish landowners.
In 1812, at the age of 38, O'Donnell migrated to the United States and took up residence in New York City, where he successfully practised as an architect.
In November he dictated his will; at that point he decided to convert from Anglicanism to Roman Catholicism.
O'Donnell converted to Catholicism on his deathbed, perhaps due to the realization that he might not be allowed to be buried in his church.