German-Americans in the American Civil War were the largest ethnic contingent to fight for the Union. More than 200,000 native Germans served in the Union Army, notably from New York and Ohio. Thousands also served in the Confederacy, being primarily descended from Pennsylvania German ancestors who had migrated to the Carolinas in the 18th century and early 19th century, along with Swabian, Swiss, and Austrian immigrants who arrived directly in the South.
Approximately 516,000 Union soldiers, or 23.4% of all Union soldiers, were immigrants; about 216,000 of these were born in Germany. New York supplied the largest number of these native-born Germans with 36,000. Behind the Empire State came Wisconsin with 30,000 and Ohio with 20,000.
Scores of individual regiments, such as the 9th Ohio, 74th Pennsylvania, 32nd Indiana (1st German), and the 9th Wisconsin Infantry, consisted entirely of German Americans. Major recruiting efforts aimed at German Americans were conducted in Cincinnati, St. Louis, and Milwaukee, among many other cities.
New York and Ohio each provided ten divisions dominated by German-born men.
Commonly referred to as "Dutchmen" by other Union soldiers, and "lopeared Dutch" by Confederates, German-American units in general earned a reputation for discipline.