Considered to be one of the most capable and effective commanders in the Western Theater of the Civil War, Peter J. Osterhaus was an adopted son of the United States, born in Coblenz, the government seat of the Rhine Province in the German Confederation, in 1823. Finding a passion in military service, Osterhaus entered the Berlin Military Academy and later served in the Prussian Army for the required one year of service. However, in 1848, like many young Germans, he actively supported the democratic and classic liberal revolutions in his home country. He joined the revolutionary army and hoped to use his military experience against the Prussian Army at Baden. By 1849, however, the revolutions against the monarchies of Europe were crushed, forcing many of the revolutionaries to flee their homelands for the world’s foremost democracy, the United States.
Osterhaus was one of hundreds of German emigrants to settle in the small Illinois town of Belleville, less than twenty miles southeast of the largest city west of the Mississippi: St. Louis, Missouri. He established himself as a businessman in Belleville and took an active role in Republican politics. In late 1860, Osterhaus moved to St. Louis, because of financial reasons. The former revolutionary could not sit quiet, though, as St. Louis became embroiled in the secession crisis. To help defend the vital Federal Arsenal in the city, he secretly trained local Germans and students in military tactics. Osterhaus’ preparedness, leadership, and love for Union helped to propel him to military command in less than one year after the war broke out in April 1861.
Instead of pursuing a Federal commission, Osterhaus wanted in on the action as soon as possible and enlisted as a private in the 2nd Missouri Volunteers, a ninety-day regiment, on April 22, 1861. The fact that he had prior military experience and bonded well with the German immigrants that made up the regiment, he was elected captain – and soon major – within two weeks. The unit, under the command of fellow German immigrant Col. Henry Boernstein, was heavily involved in the capture of the pro-secession militia encamped at Camp Jackson in St. Louis. By June, as Brig. Gen. Nathaniel Lyon – who was in command of the Department of the West – the pro-secessionist Missouri governor Claiborne Jackson and his State Guard were ousted from the capital at Jefferson City.
On August 10, 1861, the Federal troops were defeated by the Missouri State Guard under Maj. Gen. Sterling Price and Brig. Gen. Ben McCulloch’s Western Army (CS) at Wilson’s Creek. Osterhaus’ performance at Wilson’s Creek as a battalion commander went noticed by Maj. Gen. John C Fremont, who promoted him to colonel and in command of the new 12th Missouri Infantry Regiment, another ethnically German unit. The unit was trained for just under a month before leaving St. Louis on campaign to Springfield, Missouri. While on the march, Col. Osterhaus was once again promoted to brigade command by Brig. Gen. Franz Sigel.
Pea Ridge was Osterhaus’ first major engagement in independent command – leading a division in the Army of the Southwest under Maj. Gen. Samuel Curtis. Osterhaus commanded the task force that was ordered to find the main body of the Rebel army, and eventually collided with Brig. Gen. McCulloch’s much larger Confederate Division at Leetown. His artillery batteries pounded McCulloch’s troops, but was overwhelmed by the sheer size of the Confederate force. The next day, March 8, his division was once again engaged, helping to solidify Union victory at Pea Ridge. Nonetheless, Osterhaus gained valuable experience in the deployment of smaller units and artillery. Just several months following Pea Ridge and Leetown, he was promoted to brigadier general and transferred to Maj. Gen. Ulysses S. Grant’s Army of the Tennessee.
By January 1863, Osterhaus commanded a division in the XIII Corps (also designated the I Corps). Once again, his leadership was distinguished at Arkansas Post and the opening engagements of the Vicksburg Campaign, where he and Brig. Gen. James McPherson forced out Confederates from the field at Port Gibson. Osterhaus wrote in his report that, “I immediately ordered the One Hundred Fourteenth Ohio and Forty-ninth Indiana to charge the crest of the hill, which was the nucleus of the Rebel position. I led the charge personally, ordering at the same time the Forty-second and One Hundred Twentieth Ohio and Sixty-ninth Indiana, and One Hundred Eighteenth Illinois Regiments to advance in eschelon [sic]. The charge was a complete success.” His division was also heavily engaged at Big Black River Bridge and during the initial assaults on the Vicksburg defenses in May 1863. Though Vicksburg was one of the greatest victories for the United States during the war, Osterhaus had little else to celebrate. Soon after Vicksburg’s capitulation, he lost his wife.
That November, after he returned from leave, Osterhaus – along with the rest of the Army of the Tennessee – arrived in Chattanooga, Tennessee to support the Army of the Cumberland (now commanded by Maj. Gen. George Thomas), which was surrounded by Maj. Gen. Braxton Bragg’s Army of Tennessee. Bragg’s army occupied both Lookout Mountain and Missionary Ridge, and aimed to force the army’s surrender by starvation and bombardment. However, Grant, now in command of the Military Division of the Mississippi, reinforced the army with the Army of the Tennessee. Grant’s plan was to take Lookout Mountain and Missionary Ridge by double-envelopment. Unlike the rest of the Army of the Tennessee, which was to take Missionary Ridge from the north, Osterhaus’ division was selected to join Maj. Gen. Joseph Hooker’s command in the Army of the Cumberland to take Lookout Mountain after being stuck on the other side of Tennessee River after flooding destroyed the only bridge across. The first wing – including Osterhaus – was ordered to cross Lookout Creek to the north and converge with the second wing at the Craven House property on the mountain. The plans fell apart as the first wing were engaged with Confederate skirmishers along the creek, but were able to push through and up the northern end of the mountain soon after. Hooker’s army had taken Lookout Mountain and moved south into Georgia to block the Confederate retreat.
The following day on November 27, 1863, Osterhaus’ division advanced on Maj. Gen. Patrick Cleburne’s division at Ringgold Gap, where he was protecting the Confederate retreat. A combination of poor artillery placement and overwhelming numbers forced Osterhaus back in one of his only defeats. He was also present at the Battle of Resaca, but would suffer a bout of malaria by Kennesaw Mountain and remained out of the campaign until August 31, 1864, when he would use his artillery at Jonesboro to secure Union victory. His command style, leadership, and military understanding, led to his promotion to major general and commander of the XV Army Corps (Army of the Tennessee). Osterhaus’ corps was one of four army corps that made up Sherman’s army used in the March to the Sea and Carolinas Campaign. After the fall of Savannah, he was transferred to serve under Maj. Gen. Edward Canby as his Chief of Staff. He remained in this position throughout the surrender of Fort Blakeley, one of the last battles of the Civil War, and even signed the surrender documents on behalf of Union forces in the Trans-Mississippi. Though the war was officially over, for Peter J. Osterhaus, it was far from it.
Osterhaus remained in the United States Army until 1866, serving six months as the Military Governor of Mississippi at the start of Reconstruction. Following his tenure in the South, he was elected to the Board of Directors as Vice Chairman for the National Soldiers’ Home in Washington. He helped in the creation of a Beer Hall in the home – his German influence – and served alongside Andrew Johnson, Ben Butler, Salmon Chase, and Edwin Stanton to name a few. His service only lasted until 1867, when he was appointed Consul to Lyons, France by Johnson from the recommendation of Grant. He and his new wife Amelie – along with their children (with the exception of Hugo, who was to attend the US Naval Academy) – moved to France, close to Osterhaus’ birthplace along the Rhine. He served in Lyons for eleven years. However, his love of his homeland attested to the fact that his family moved to Mannheim in western Germany soon after, where he served as the US Vice-Consult there until 1905.
The last twelve years of his life were marked by his retirement, but the downfall of peace in Europe. Mannheim became an industrial center of military materiel to supply the German Army in the Great War. Yet, because of its strategic importance, Osterhaus’ new home was bombarded by the Royal Air Force in 1915. Fifty years after the devastation of the Civil War, it would have been heartbreaking for a Civil War veteran, like Osterhaus, to witness the industrialization of warfare, resulting in the deaths of millions of Europeans. Between 1915 and 1917, he moved to Duisberg, Germany, where he later died on January 2, 1917. He was buried in his hometown of Koblenz, in the Jewish Cemetery there. Unfortunately, due to erosion and the construction of a new road nearby, his headstone no longer remains. Luckily, Mary Townsend, Osterhaus’ biographer, has started a campaign to save his grave.
Townsend, Mary. “Biographical Sketch.” Peter Joseph Osterhaus. Website. Accessed July 5, 2018. http://www.pjosterhaus.com/bio.html.
Townsend, Mary. Yankee Warhorse: A Biography of Major General Peter J. Osterhaus. Columbia: University of Missouri Press, 2010.
Woodworth, Steven E., Grant’s Lieutenants, vol. 1: From Cairo to Vicksburg, Lawrence: University of Kansas Press, 2001.