1861: The Missouri Campaign, Brig. Gen. Nathaniel B. Lyon, commander
- The Camp Jackson Action
Maj. Osterhaus led the rifle battalion of Heinrich Boernstein's 2nd MO Infantry (3 month enlistees) in Lyon's controversial movement to capture the state militiamen drilling at this camp. Fire was exchanged with civilians, casualties on both sides. (See Rombauer, Union Cause in St. Louis, 1909, and Boernstein, Memoirs of a Nobody)
- The Battle of Boonville
Maj. Osterhaus's skirmishers led the way into this brief fight, the first battle of the war west of the Mississippi. (See Dyer's Boonville, an Illustrated History)
- The Battle of Wilson's Creek
Maj. Osterhaus's battalion led the way in, was the last off the field, and protected both flanks at various times during the battle. (See Wilson's Creek by Piston and Hatcher; go to Wilson's Creek for Osterhaus's report)
1862: The Arkansas Campaign, Maj. Gen. Samuel R. Curtis, commander
- The Battle of Pea Ridge
Col. Osterhaus, with practical command of Brig. Gen. Franz Sigel's division, led a large detachment at Leetown that essentially took one half of Maj. Gen. Earl Van Dorn's army out of the fight, its leaders killed or captured. Next day he was instrumental in critical artillery placement that helped secure the victory for Curtis. (See Pea Ridge, by Shea and Hess)
- Searcy's Landing Skirmish
Col. Osterhaus's division held the forward outpost in Curtis's failed movement on Little Rock. One of his foraging details was mauled by irregulars and Confederates, contributing to Curtis's decision to abort the campaign. (See A Severe and Bloody Fight, by Akridge and Powers)
1863: The Vicksburg Campaign, Maj. Gen. U. S. Grant, commander
- The Battle of Arkansas Post
Brig. Gen. Osterhaus, commanding the Second Division of Brig. Gen. George Morgan's corps, helped win this assault against a well-fortified position by his effective use of artillery. (See Webster and Cameron's History of the 1st Wisconsin Light Battery, 1907 and, of course, The Vicksburg Campaign in three volumes by Ed Bearss for the entire campaign)
- The Battle of Port Gibson
Osterhaus, commanding McClernand's Ninth Division in this campaign, fought the terrain as much as the Rebels in this frustrating fight, finally forcing Brig. Gen. Edward Tracy's Alabama brigade to abandon the field with the help of a flanking movement by McPherson. (Go to Port Gibson for Osterhaus's report)
- The Battle of Champion Hill
Osterhaus held the middle of the long and disjointed Union line in this pivotal battle but did little other than help convince Lt. Gen. John Pemberton that he should retreat by applying pressure late in the day.
- The Battle of Big Black River
Osterhaus sustained a shrapnel wound on his thigh shortly before Brig. Gen. Mike Lawler's spectacular charge so he missed the action. He resumed command of his Ninth Division the next day.
- The Two Assaults on fortress Vicksburg
Osterhaus led his Ninth Division against Square Fort at the left end of the Union line, with no more results than the rest of the attackers enjoyed either day. Grant then pulled him to the Big Black for the next month to guard his back against Gen. Joe Johnston during the siege.
- The Siege of Jackson
After Vicksburg fell, Osterhaus led the chase against Maj. Gen. John Breckenridge and Johnston as they raced back to Jackson and then took part in the siege, persuading the Confederates to abandon the capital.
The Chattanooga Campaign, Maj. Gen. U. S. Grant, commander
Oct. 20, 21
Cane Creek Skirmishes
- Tuscumbia Skirmishes
Grant chose Osterhaus, now in command of the First Division of Sherman's XV Corps, Army of the Tennessee, to lead the advance eastward across northern Alabama to relieve Maj. Gen. William Rosecrans's Army of the Cumberland, cornered in Chattanooga. On this trek, Osterhaus fought almost daily skirmishes, mostly against Maj. Gen. Steven D. Lee's cavalry.
- The Battle of Lookout Mountain
Osterhaus returned from emergency leave because of his wife's sudden death just in time to help Joe Hooker plan and execute this successful assault. His artillery placement again wreaked havoc with the Confederate forces, commanded by Maj. Gen. Carter Stevenson. (See Sword's Mountains Touched with Fire and Cozzens, Shipwreck of their Hopes for general accounts of this campaign)
- The Battle of Missionary Ridge
Again in the advance of Hooker's command, Osterhaus pushed toward Rossville Gap and discovered a road running behind Gen. Braxton Bragg's position, then leading the charge that successfully flanked the Confederates off the ridge. (See Maj. Gen. William "Baldy" Smith's account of this maneuver in vol. 8 of the Papers of the Military Historical Society of Mass., 1910)
- The Battle of Ringgold Gap
Here Osterhaus's First Division faced the formidable Maj. Gen. Pat Cleburne, defending the gap to make good Bragg's escape. Osterhaus was stymied by Cleburne's superior defensive position and his own lack of artillery support, sustaining severe casualties for no gain. (Keith Bohannon's excellent unpublished report of this battle is at the Chickamauga/ Chattanooga National Military Park)
1864: The Atlanta Campaign, Maj. Gen. William T. Sherman, commander
- The Battle of Resaca
Except for a flanking movement to the south, Osterhaus's First Division's capture of an advanced postion against Lt. Gen. Leonidas Polk was Sherman's only success in this engagement, which ended with Johnston slipping out during the night. (See Secrist, Battle of Resaca and, for the entire campaign, Castel, Decision in the West)
- The Battle of Dallas
Osterhaus's brigades were split in this sharp little action against Gen. William Bate's division, in which Gen. Joseph Lewis's 1st Kentucky "Orphan" Brigade lost nearly half its men.
- The Battle of Kennesaw Mountain
Osterhaus was supposed to start in this battle but his division was relegated to reserve at the last minute, probably due to a severe attack of malaria he was suffering. Just as well; the Union losses in this battle were heavy. Only Osterhaus's skirmishers saw action here in support of Morgan Smith's Second Division.
- The Battle of Jonesboro
After a month of sick leave which caused him to miss the battles for Atlanta, Osterhaus returned to play a key part in the final battle of the campaign at Jonesboro, again by his adroit artillery placement.
The March to the Sea
- The Battle at Griswoldville
One of Osterhaus's First Division brigades greatly overmatched a rag-tag rebel force under Brig. Gen. Pleasant Philips in the only battle of the march. (See Bailey, War and Ruin and Glatthaar, March to the Sea and Beyond, for general accounts)
- The Capture of Fort McAllister
Osterhaus's Second Division, under Brig. Gen. William Hazen, reduced the lightly defended fort in twenty minutes. Osterhaus was not on hand for this assault.
1865: The Mobile Bay Campaign, Maj. Gen. E. R. S. Canby, commander
Mar. 27-Apr. 8
- The Siege and Assault of Spanish Fort
- The Siege and Assault of Fort Blakely
Osterhaus was Canby's chief of staff on this campaign, coordinating troop movements and logistics for the siege and assaults, the last battles of the war. (See Hearn, Mobile Bay and the Mobile Campaign, and O'Brien, Mobile, 1865)
My new book has detailed descriptions of these engagements from Osterhaus's part of the field.