1861

November 7

Organization begun at Camp McLain, Cincinnati, Ohio under Colonel Nathaniel C. McLean, Lt. Colonel R.A. Constable and Major Robert Reily.

1862

January 8

Organization completed

January 28

Left State for Grafton, Va. Attached to Milroy's Command, Cheat Mountain, District West Virginia

February 17-March 1

March to Huttonville and attached to Milroy's Brigade, Dept. of the Mountains

April 1-12

Expedition to Lost River Region attached to Schenck's Brigade, Dept. of the Mountains

April 12

Action at Monterey

May 8

Battle of McDowell

The Regiment lost 87 men

May 10-12

Retreat to Franklin

May 29

Franklin

June 1-2

Pursuit of Jackson to Shenandoah Valley, Strasburg and Staunton Road

June 3

Mt. Jackson

June 4

New Market

June 6

Harrisonburg

June 8

Battle of Cross Keys

June

At Middletown, attached to 2nd Brigade, 1st Division, 1st Corps, Army of Virginia. Colonel McLean is given command of the brigade

July 7

At Sperryville

July 16-19

Reconnaissance to Madison Court House

August 9

Battle of Cedar Mountain

August 16-
September 2

Pope's Campaign in Northern Virginia

August 22

Freeman's Ford

August 29-30

Battle of Bull Run

The Regiment lost 113 men. The colors were riddled with over 90 holes.

September-December

Duty in the Defenses of Washington, D.C. attached to 2nd Brigade, 1st Division, 11th Army Corps, Army of the Potomac

September 25-28

Expedition from Centreville to Bristoe Station and Warrenton Junction

November 29

Colonel Nathaniel C. McLean promoted to brigadier general

December 3

Lt. Colonel R.A. Constable promoted to colonel and Major Reily to lieutenant colonel

December 10-15

March to Fredericksburg, Va.

1863

January 12

Colonel Constable resigned

January 20-24

"Mud March"

February-April

At Falmouth

February 26

Woodstock and Cedar Run

March 3

Lieutenant Colonel Reily promoted to colonel

April 27-May 6

Chancellorsville Campaign

May 1-5

Battle of Chancellorsville

The Regiment in a half hour lost 150 casualties, including Colonel Reily, who was was mortally wounded.

May 22

Andrew L. Harris promoted to colonel

June 11-July 24

Gettysburg Campaign

July 1-3

Battle of Gettysburg

The 75th Ohio was commanded at Gettysburg by Colonel Andrew L. Harris, who took command of the brigade on July 1. Captain George B. Fox then took over the regiment.

The Regiment lost 16 killed 16, 96 wounded 96, and 71 missing, a total of 183.

From the monument: "Arriving at Gettysburg from Emmitsburg July 1, 1863, The 25th and 75th Ohio Infantry advanced beyond the town and, under a heavy cannonade, took position here, supportingBattery G, 4th U.S. Artillery. During July 2 and 3, they held an advanced line on East Cemetery Hill, and early July 4 led the advance into the town."

July 5-24

Pursuit of Lee

August 6-12

Moved to Morris Island, S.C. and attached to 2nd Brigade, Gordon's Division, Folly Island, S.C., 10th Army Corps, Dept. of the South

August 18-
September 7

Siege operations against Fort Wagner, Morris Island, S.C., and against Fort Sumpter and Charleston

September 7

Capture of Fort Wagner and Gregg, Morris Island

September

Moved to Folly Island, S.C.

1864

February 6-14

Expedition to John's and James' islands

February 22

Ordered to Jacksonville, Fla. Regiment mounted and attached to 1st Brigade, Ames' Division, District of Florida

April 2

Expedition from Jacksonville to Cedar Creek; Cedar Run

April 25-May 10

Expedition to Headwaters of the St. Johns and Kissinee Rivers, destroying and capturing a large amount of stores and property. Attached to District of Florida, Dept. of the South

April 28

Action near Jacksonville

May 25

Near Camp Finnegan

May 31-June 3

Expedition from Jacksonville to Camp Milton

July 3

King's Creek, S.C. (Detachment)

July 23-28

Raid from Jacksonville to Baldwin

July 25

Near Trail Ridge

July 26

Action at St. Mary's Trestle

August 12

Camp Baldwin

August 15-19

Raid on Florida Railroad

August 17

Gainesville

September 28

Expedition to Enterprise

October - November,

Companies A, B, C, D, F and G mustered out. Remaining companies attached to 4th Separate Brigade, Dept. of the South

December 8-10

Companies E, H, I and K moved to Hilton Head, S.C. and attached to 1st Brigade, Coast Division, Dept. of the South

December 29

Pocotaligo Bridge, S.C.

1865

January

Returned to Florida and duty at District Headquarters, Jacksonville, and at Tallahatchie, Fla. attached to 4th Separate Brigade, Dept. of the South

July 15

Mustered out