Other than the indigenous inhabitants who populated what is now Arizona in prehistoric times, the Spanish Conquistadors were the first “military” to explore what is now Arizona in the 16th century.  In their quest for gold, they mined and subjugated those with whom they came in contact to do their bidding.  As the Spanish further populated Latin America and moved north through Mexico to present day Arizona and beyond, they brought their customs, culture, and religion.  They built presidios (e.g., Tubac and Tucson) and missions (e.g., Tumacocri and San Xavier) and developed the Southwestern United States. Tucson was a Spanish presidio (fort and settlement) in 1775 before the U.S. Declaration of Independence.  In 1821, Mexico won its independence from Spain.  In 1848, the U.S. won its war with Mexico, and U.S. troops patrolled from Fort Yuma just across the Colorado River to protect the gold seekers on their way to California in 1849.  With the signing of the Gadsden Purchase in 1853, Arizona acquired the land from the Gila River to its present boundary with Mexico.

From the late 1850s to the late 1880s military units were fighting the Indian Wars.  During the Civil War the military was fighting in the East, but the Apaches were raiding ranches, Overland Stage stations, and wagon trains.  Military posts--Fort Defiance, Fort Whipple, Fort Apache, Fort Verde, Fort McDowell, Fort Lowell, Fort Bowie, etc.--were scattered throughout Arizona.  During the Civil War three skirmishes occurred in Arizona between soldiers of the North and South—Picacho Peak, Stanwix Station, and La Paz on the Colorado River.  The South was interested in the gold in California, and the North was going to protect it.

With the Civil War still going on and Carleton still fighting the Navajos, the U.S. War Department therefore authorized Governor John Noble Goodwin of Arizona to raise five companies of Arizona Volunteers in 1864. Recruitment was delayed for a year, but by the fall of 1865, more than 350 men had been issued into service under the command of nine officers. The overwhelming majority was Mexicans, many of them from Sonora, or O'odham and Maricopas from the Gila River villages, who had grown up fighting Yavapais and Apaches, as had their fathers and grandfathers.
For the next year, they guarded wagon trains between Prescott and La Paz and campaigned relentlessly across central Arizona. According to the Third Arizona Territorial Legislature, the volunteers inflicted "greater punishment on the Apaches than all other troops in the territory." Traveling "barefoot and upon half rations," they killed 150 to 173 Apaches and Yavapais while losing only ten men in combat themselves. If their enlistments had been extended, as many territorial officials and army officers requested, the centuries-old alliance of Hispanic, O'odham, and Maricopa frontiersmen might have conquered the Apachería for the Anglo newcomers.  The Apache problem was finally quelled with the surrender of Geronimo in 1886 at Fort Bowie.

When the Spanish-American War began in 1898, Arizona provided two troops of 250 men to go to San Antonio, Texas.  There, the recruits became part of the First Volunteer Cavalry, or as their executive officer, Lt. Colonel Theodore Roosevelt, used to call them--the “Roughriders”.

In 1916, during the Mexican Revolution, Pancho Villa’s men killed 17 Americans in Columbus, New Mexico.  President Wilson sent General Black Jack Pershing into Mexico with an expeditionary force to kill or capture Villa.  The First Infantry Regiment of the Arizona National Guard was part of General Pershing’s army and was mobilized to assist Pershing’s troops by guarding and patrolling the border between Douglas and Naco, Arizona.  The First Arizona Infantry Regiment continued its mission on the border until World War I was declared on April 6, 1917.

The First Infantry Regiment was drafted into federal service in 1917, re-designated as the 158th Infantry Regiment and sent overseas in July and August 1918.  In France, the 158th Infantry was assigned to a division, which furnished replacement personnel to other units.  The 158th Infantry was honored to act as guard of honor to President Wilson during his residence in France in 1918, and the 158th Infantry Band was chosen as Wilson’s honor band.  The regiment was mustered out of federal service on May 3, 1919.

On 16 September 1940, with the declaration of the National Emergency, the 158th Infantry joined its parent organization, the 45th Division at Ft. Sill, Oklahoma.  After December 7, 1941 attack on Pearl Harbor, the 158th Infantry Regiment was removed from the 45th Division and became a separate Regiment.  In January 1942, the Regiment embarked at the Port of New Orleans and disembarked in the Canal Zone.

In Panama they trained in jungle warfare and become famous for jungle-fighting skills.  The Regiment took the name of the Bushmasters after the deadly bushmaster snake, which became the distinguishing shoulder patch of the 158th Regimental Combat Team. The name "Bushmasters" became well known through the National press. General Mac Arthur, himself, personally selected and requested that the Bushmasters be sent to his command in the Southwest Pacific Theater.

The “Bushmasters” were General Douglas Mac Arthur’s point (lead) element in many actions.  After being relieved by divisions in various campaigns in which they distinguished themselves across the Pacific, the 158th Infantry was selected to spearhead the final invasion of Japan. The Bushmasters were under orders to proceed two days ahead of America's crushing D-Day to silence Japanese air warning stations south of Kyushu.  The timely capitulation of Japan saved the 158th Infantry from what many believed would have been a certain suicide mission. In October 1945, the 158th Infantry landed in Yokohama, Japan, and members were then shipped home as the 158th was deactivated at Utsunomiya, Japan on January 17, 1946 General Mac Arthur gave the Bushmasters the accolade, “No greater fighting combat team has ever deployed for battle”.

The Arizona National Guard retained the 158th Infantry until the unit converted into Military Police and Transportation Corps units effective December 7, 1967.  The Headquarters, 153rd Artillery Brigade carried on the lineage and distinctive insignia of the 158th Infantry.  Today the 1/158th Infantry assumes the lineage.

Arizona’s military history also involves the numerous Army Air Corps training fields scattered throughout the state without which thousands of pilots would never have been trained to support the war effort.  After the war, the Air Force was formed as a separate service, and Major General (Ret.) Barry M. Goldwater was instrumental in the creation and development of the Air National Guard.  The Arizona Air National Guard continues to have vital missions with air refueling missions, foreign nations’ fighter training, Weapons Directors’ training, and MQ-1 Predator (UAV) missions.

Both the Army and Air National Guard were involved in the Berlin Crisis.  The 161st Fighter Group, Air National Guard and the 222nd Transportation Company of Winslow, Arizona were mobilized and supported this Cold War effort.

Arizonans have answered their nation’s call to arms to support national policy through Korea, Viet Nam, Panama, Grenada, Desert Storm, Afghanistan, and Operation Iraqi Freedom.  Members of the Arizona National Guard are deployed to Afghanistan, Iraq, and elsewhere in the service of their country as of this writing.