Following the Hungate massacre that killed a family of four–including two children under three years old–Governor John Evans authorized the creation of the 3rd Colorado Cavalry Regiment in August 1864 to provide defense against Native Americans.

The 1st and 3rd Colorado Cavalries, led by Chivington, launched an attack against an encampment of Arapaho and Cheyenne in modern-day Kiowa County in what is now known as the Sand Creek massacre.

[5] A Joint Committee on the Conduct of the War investigation declared the Chivington had ordered and led "a foul and dastardly massacre which would have disgraced the veriest savage among those who were the victims of his cruelty.

In March that same year, the Colorado Labor Wars began when discontented gold and silver miners, led by the WFM, went on strike throughout the state.

[10]: 3  On 4 December 1903, the governor declared Teller County to be in a "state of insurrection and rebellion," but by 28 January 1904 had assessed that the situation to be "rapidly changing" and suspended military authority, but left the soldiers in the region for almost three more months.

[10]: 16–17  In March 1904, WFM offices were reported to be displaying U.S. flags defaced with words "deemed of obnoxious character," which were seized and destroyed by troops.

The strike targeted in particular the partially Rockefeller-owned Colorado Fuel and Iron Company (CF&I) in Huerfano, Las Animas, and Pueblo counties.

After over 10,000 miners were evicted from company-owned towns across Southern Colorado in the immediate aftermath of the strike's declaration, sporadic violence began between strikers and the company-backed strikebreakers, mine guards, and deputized local militia hired by Baldwin-Felts detectives.

[14]: 141  A company from the National Guard and four artillery pieces arrived in the strike zone by train on 9 October 1913 to supplement a growing local militia.

[15] On 1 November, after an agreement between General Chase and John R. Lawson, the National Guard marched between the mines and tent colonies to effect disarmament on both sides.

[15][16] After six months of having soldiers deployed to the southern part of the state and with tensions easing due to the pacifying influence of union leader Louis Tikas and the National Guard–and despite a murder in Forbes in March 1914 that saw the Guard burn a striker tent colony down–the vast majority of the troops are withdrawn back towards garrisons in Denver in mid-April 1914 to reduce cost.

Major Patrick Hamrock and Linderfelt organized the battle against the strikers, which killed around twenty on the UMWA side, including at least eleven women and children who died in a fire started by the soldiers and a boy struck by a machine gun bullet.

[14]: 221 During the following week, strikers sought revenge against the mining companies and National Guard, launching dozens of deadly attacks across the state in what became known as the 10-Day War.

Captain Hildreth Frost led a small group of National Guard troops on 28 April in the northernmost battle at a mine in Louisville.

[13]: 206  The fighting ceased on 29 April after President Woodrow Wilson ordered the federal-level Army to disarm the strikers and turn-back the National Guard.

In June 1916, prior to the United States' involvement in the First World War, the Colorado National Guard was deployed to the Mexican–American border to support General Pershing's expedition against the Mexican revolutionary Pancho Villa.

Despite this, it was mustered against striking Denver Tramway Company workers in August 1920, where the Guard’s limited numbers meant it was unable to effectively break up the strikers.

[21] As Adjutant General, Hamrock ordered the National Guard and the statewide police force, the Colorado Rangers, to subdue striking miners in 1922.

[24] On 18 April 1936, during the economic trials of the Great Depression and Dust Bowl, Governor Edwin C. Johnson declared martial law and ordered the closure of Colorado’s southern state borders to migrants.

Following a threatened boycott of Colorado businesses by New Mexico and New Mexican Senators Dennis Chávez and Carl Hatch condemning the measures as unconstitutional, the governor lifted his orders after only ten days.

[citation needed] Camp George West near Golden, constructed as a training facility for Colorado National Guardsmen in 1903, was utilized as a rifle range during the war.

Two of the airmen did not return following crashes in 1969: Maj. Clyde Seiler was killed when his F-100 was brought down by ground fire during a combat mission and intelligence officer Capt.

Departing in late January 2021, the unit joined elements of the Vermont National Guard, aligned with the 86th Infantry Brigade Combat Team.

The United States Forest Service certifies Colorado Army National Guard helicopter pilots who fly UH-72 Lakotas, UH-60 Black Hawks, and CH-47 Chinooks.