According to the 1860 Census, 1,611,214 Americans had been born in Ireland. Of these 84,673 were living in Southern states that seceded and joined the Confederacy. Only 4,906 lived in South Carolina. 57,206 lived in Louisiana, Tennessee and Virginia. Many, if not most, of the 84,673 were not Irish Catholics. Of the 84,673 about twenty percent were males of military age (18-45), about 17,000. Only about 60 percent actually served in the Confederate army, about 10,000, if that. The Irish contribution to the Confederacy was inconsequential. On the other hand we know that over 200,000 Irish immigrants fought for the Union and many more of their children, notably Grant, Meade, Sherman, Reynolds, Sheridan, the Mahans, and Michael Healy (one of the first African American officers commissioned by Lincoln).
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In 1856, its last year of existence before its Northern branch merge with the Republicans, the American (Know Nothing) Party received 872,703 votes. 307,843 came from Southern states that would join the Confederacy. The Know Nothings received an additional 185,776 votes from states where there were deep Southern roots and Confederate sympathies: Missouri, Kentucky, Maryland, and Indiana. Despite strong Know Nothing sympathy in Massachusetts and New England, the Know Nothing movement was strongest in the South.
