Prior to the American Civil War it was one of the three regiments which formed the Fourth Brigade of the First Division of the New York State Militia.

[2] The 79th New York (348 strong in Spring 1859) was part of 1st Division, 4th Brigade of the New York Militia, the regiment was designated as light infantry cross trained train [clarification needed] as heavy artillery for the defense of Manhattan and also provided parade and guard for dignitaries such as the Prince of Wales and the Japanese ambassador when they visited Manhattan[clarification needed].

The 79th, without knowing it, set themselves up to take part in nearly every major engagement in the eastern theater of the war and became one of the most known and traveled regiments in the Union Army.

The inspector was informed by Col. McLeays that: "Their stuff for trousers was expected to arrive from Scotland daily, when they would immediately put their uniforms under contract for manufacture".

The Regiment was quartered at Georgetown College, recently vacated by the 69th N.Y.S.M, and spent their first few couple weeks in Washington filling their time with drill and guard mounts.

At the First Battle of Bull Run on 21 July 1861, the Third Brigade of Tyler's First Division, under Colonel William Tecumseh Sherman, consisted of four regiments of infantry (2nd Wisconsin, 13th, 69th, and 79th New York) and a battery of artillery, the 3rd United States Artillery, Company E. The 79th New York experienced some of the fiercest fighting and suffered some of the highest Union casualties at First Bull Run (referred to by the Confederates as First Manassas) although, to begin with, it appeared that they would miss the action.

As Confederates fled from the initial Union attack and withdrew up the hill past the Henry House, Private Todd stepped out of line calling to Colonel Sherman, "Give us a chance at 'em before they get away".

His sergeant, a British Army veteran, dragged him back into line, growling "shut up your damned head - you'll get plenty of chance before the day is over".

It was a costly mistake - "As we lowered our arms and were about to rally where the banner floated we were met by a terrible raking fire, against which we could only stagger".

There they remained for two more hours while the attack was pressed by other Union regiments with an equal lack of success, until all were finally driven from the plateau by Confederate reinforcements.

"Spades were trumps" quipped one New Yorker "and everyman held a full hand" On the morning of 14 August 1861, the Highlanders, together with the 13th and 21st New York volunteer infantry regiments, mutinied and demanded an adjustment of certain perceived grievances.

They also objected to having a new colonel, Isaac Ingalls Stevens, appointed on 30 July to replace James Cameron (killed at First Manassas), rather than being able to elect their own commander as was the custom with militia units.

When the mutineers, who had not anticipated such a response to their complaints and whose own arms were stacked, were ordered to cease their mutiny, they recognised the futility of their position and speedily submitted.

A contemporary account in the publication Harper's Weekly noted, "The scene during the reading of the order of General McClellan was exceedingly impressive.

The sun was just going down, and in the hazy mountain twilight the features and forms of officers and men could scarcely be distinguished, Immediately behind his aide was General Porter, firm and self-possessed.

In the rear of the regulars, and a little distance apart, General Sickels sat carelessly on horseback, coolly smoking a cigar and conversing with some friends.

Instructed not to undertake any offensive operations Benham, over the objections of his Division commanders, ordered a futile attack on Confederate general, N. G. "Shanks" Evans.

He died amid the cheers of victory with the color staff gripped firmly in his hand almost at the same time and nearly on the same ground as Major General Philip Kearny.

The 6th Louisiana was the most thoroughly Irish of all the Tiger regiments, with the result that the battle in a raging thunderstorm devolved into Celt-on-Celt, hand-to-hand combat, and eventually sputtered to an indecisive end in rain and darkness.

During the latter battle, the Highlanders fought near Burnside's Bridge and were deployed as skirmishers leading an advance along the Sharpsburg Road near the Sherrick House.

They travelled by side-wheel steamer down the Ohio River, which was described as being of such shallow draft "it could sail on a heavy dew", and broke their journey at Louisville to spend a riotous couple of nights in the town's bars and "parlour houses", a euphemism for brothels, before arriving at the front.

The regiment was too late to take part in the Siege of Vicksburg, but instead was sent to Jackson to tear up rail tracks and destroy the Mississippi Central Railroad at Madison Station.

August found the regiment back once more with the Army of the Ohio, in time to take part in Burnside's campaign in East Tennessee, seeing action at Blue Springs, Lenoir and Campbell's Station.

Longstreet ordered the brigades of Humphreys' Mississippians and Bryan and Wofford's Georgians, approximately 3,000 men, to make a surprise attack on the fort.

The night of 28 November was bitterly cold as the Confederate troops quietly moved into position just 150 yards from the fort, but, in spite of their caution, the defenders overheard them and were prepared for the coming assault.

At first light, the Confederates began their attack, struggling through telegraph wire entanglements which the Federals had stretched between stakes a short distance in front of the ditch.

They found that there were no scaling ladders with which to climb the slope up to the parapet and the situation was further aggravated by the ground being frozen and covered in sleet which caused the soldiers to lose their footing and fall.

Francis W. Judge of Company K, 79th NY, grabbed the flag of the 51st Georgia from their color bearer and, in spite of a concentrated and deadly fire, was able to return in safety with his trophy into the fort.

In April, the Highlanders rejoined the Army of the Potomac in time to fight at the battles of the Wilderness and Spotsylvania, being engaged in the assault on the salient known as the "Mule Shoe."

It continued duties at Washington until the men were eventually mustered out of Federal service on 14 June 1865, whereupon the regiment returned to state militia status.