Approximately 516,000 (23.4% of all Union soldiers) were German-Americans; about 216,000 were born in Germany. (...)
Commonly referred to as "Dutchmen" among other Union soldiers, German-American units in general earned a reputation for discipline and ruthlessness (...)
A popular Union commander among German-Americans, Major General Franz Sigel was the highest ranking German-American officer in the Union Army, with many Germans claiming to enlist to "fight mit Sigel." Sigel was a political appointment of President Abraham Lincoln, who hoped that Sigel's immense popularity would help deliver the votes of the increasingly important German segment of the population. He was a member of the Forty-Eighters, a political movement that led to thousands of refugees fleeing to the United States, including several future Civil War officers such as Carl Schurz, August Willich, Louis Blenker, Max Weber, and Alexander Schimmelfennig.
Schurz was a part of a politico-social movement in America known as the Turners, which were supportive in getting Lincoln elected as President. The Turners provided the bodyguard at Lincoln's inauguration on March 4, 1861, and also at Lincoln's funeral in April 1865.
Other prominent German-born generals included Godfrey Weitzel, Adolph von Steinwehr, Edward S. Salomon, Frederick C. Salomon, and August Kautz. Hundreds of German-born officers both led and served in regiments during the war, including Col. Gustav Tafel, Col. Paul A. Frank, Col. Friedrich Hecker, Maj. Jurgen Wilson, and Lt. Theodore Schwan. Among the very best Union artillerists was German-born Capt. Hubert Dilger, who had been trained at the Karlsruhe Military Academy.