This article by the Irish Independent points out that the first Union private and the last Union general killed in the war were both Irish. It’s a brief look at the impact Irish immigrants had on the American cataclysm.
They reckon that 210,000 Irish soldiers fought in British uniform in the First World War, and that 49,300 were killed. Yet almost as many Irishmen fought in the American Civil War – 200,000 in all, 180,000 in the Union army, 20,000 for the Confederates. An estimated 20 per cent of the Union navy were Irish-born – 26,000 men – and the total Irish dead of the American conflict came to at least 30,000. Many of the Irish fatalities were from Famine families who had fled the desperate poverty of their homes in what was then the United Kingdom, only to die at Antietam and Gettysburg. My old alma mater, Trinity College Dublin, is collating the figures and they are likely to rise much higher as Irish academics mine into the American Compiled Military Service Records for the regiments of both sides.