Soldiers from a wide variety of ethnic backgrounds participated in the Civil War. Of approximately 2 million Union soldiers, nearly a quarter were foreign born. An estimated 175,000 were German, 150,000 were Irish, and 50,000 were English or Canadian. Native Americans also fought on both sides, as did a number of Hispanics and Scandinavians. Immigration continued almost unabated in the North throughout the war, and many newcomers showed their gratitude by joining the Union army within months of their arrival.

Irish Americans in particular played an integral role in the war. Many had immigrated in the thirty years before the war; New York and Boston both contained large Irish enclaves. According to the 1860 census, more than 1.5 million Americans claimed to be from Ireland. The number of soldiers of Irish descent in the Union army is well verified, but statistics regarding the Confederacy are almost unknown. Still, Southern songs of the era suggest a strong regional Irish influence.

Northern Europeans

The Irish at this time in American were singled out for distrust and harassment. Many factories and businesses refused to hire people with Irish names. After the war, many Irish veterans returned home to face the same bigotry and biases that had hounded them prior to military service.

A large number of Germans also immigrated to the United States in the decades preceding the war. Most German, Austrian, and Dutch immigrants made their homes in areas that reminded them of their homeland, places such as Pennsylvania, Delaware, and Virginia. When the war broke out, they enlisted without hesitation, and many German Americans rose to positions of great importance within the Union army.

Scandinavian Americans served primarily in the Union army because the vast majority of them had settled in the Northern states. In addition, most Swedes, Norwegians, and Danes were opposed to slavery. A large percentage of the Scandinavian Americans who fought for the Union joined the navy. One of the most prominent was John Ericsson, a Swede who invented the propeller and designed the first Union ironclad ship, the Monitor.

Native Americans

The war years were difficult for the Native American peoples, most of whom were struggling for their own independence and autonomy. Some tribes, such as the Cherokee, participated directly in the war; others, especially those in the east, decided whether to get involved on an individual basis. Many tribes realized that the war offered an opportunity for them to reclaim lands that had been taken from them, because it meant fewer federal soldiers overseeing their territories.

According to government records, approximately 3,600 Native Americans served in the Union army. One of the best known was Colonel Ely Parker, a Seneca who served as an aide to Ulysses S. Grant and transcribed the terms of Lee's surrender at Appomattox.

Statistics regarding Native American participation on the Confederate side are unavailable, but many did serve the Southern cause. Probably the best known is Brigadier General Chief Stand Watie, who was three-quarters Cherokee and organized a regiment known as the First Cherokee Mounted Rifles. Watie and his men fought bravely in a number of battles, and Watie has the distinction of being the last Confederate officer to lay down arms — more than two months after Lee's surrender.