Colonel Peter Joseph Osterhaus
Commander, 1st Division
Osterhaus was born in Koblenz, Prussia in 1823 and was educated at a Berlin military academy. Like his friend Sigel, he left Germany after participating in the 1848-49 revolutions. He settled in Illinois where he established himself as a merchant and postmaster. He was also active in politics, where he became a supporter of the Republican Party and became acquainted with Abraham Lincoln.
In 1860, he and his family move to Saint Louis where he established himself as a merchant and bookkeeper. He became active in the German-American community and helped train pro-Union "Homeguard" companies. When war broke out, he was promoted to Major and led a battalion of infantry at Wilson's Creek. At the battle, he distinguished himself as a brave and able commander. For his actions, he was promoted to Colonel and given command of the German-American 12th Missouri Infantry. When Curtis organized the Army of the Southwest along ethnic lines, Osterhaus was given command of the largely-German 1st Division.
After Pea Ridge, he was promoted to Brigadier General and was transferred, along with many of his German troops, to General Grant’s Army of the Mississippi. He was instrumental in the capture of Fort Hindman at the Battle of Arkansas Post and skillfully led his division throughout the Vicksburg campaign (where he was wounded) and in the operations to break the siege of Chattanooga. In 1864, he was promoted to Major General and given command of the XV Corps, which he led throughout the rest of the war.
When the war ended, Osterhaus was appointed as the U.S. Consol at Lyon, France. He served in this capacity for the next 13 years. In 1880, he returned to Germany, and established himself in business in Mainheim and was later appointed U.S. Consol in Mainheim. He remained in Germany after his retirement in 1900. He was the last surviving Major General to have served in the Union Army during the Civil War. He died in 1916.