The Battle of Tucson, also known as the Battle of the Santa Cruz, was an early engagement during World War I between the United States and the Confederate States, fought in the city of Tucson in modern-day Arizona. The battle was fought between September 4-9, 1913 and was the first major American victory of the war and would presage a series of spectacular American victories over the Confederates in the West over the course of the first eighteen months of the war. In all, there were 5,788 casualties for the US Army and 6,145 casualties for the Confederate Army, and the town of Tucson would be controlled by the Union for the remainder of the war.
Tucson was a strategic town in that it was the capital of the Arizona Territory, the largest city in the Confederate West and was located 60 miles from the border with Mexico. In addition, Tucson was the terminus of both the New Mexico Consolidated Railroad, which connected the West to New Orleans via Mesilla and Dallas, and the Occidental International Railroad, which connected the western Confederacy to southern Mexico and had been completed only a few years earlier. Control of both railroads was viewed as crucial to both sides of the conflict - the Americans (correctly) anticipated that the Meixcan Army would use it to attack Southern California via Arizona, and the Confederates (correctly) anticipated that the West would be the most vulnerable part of the Confederacy to an attack.
Despite preparations for an American attack on Tucson, the Army of Arizona, 25,000 strong with many volunteer units from the Territorial Militia, was woefully undersupplied and outgunned when the United States 10th Army arrived in the vicinity of Tucson on September 3rd. With Confederate victories in the East in the early stages of the war, the Confederate commander at Tucson, Lt. Gen. William Benjamin Craig, was confident in his force's ability to repel American forces, particularly in his establishment of the Valley Line, a defensive trench northwest of the main settlement between the northern end of the Tucson Mountains and the Santa Catalina Mountains, anticipating an attack from that direction. Aware based both on scouting and the geography of the region, US Army Group West leader Fred Funston ordered Maj. Gen. Charles T. Menoher to send half of his force, the 42nd "Rainbow" Division, directly over the Tucson mountains while his other force swept south of the mountains to seize the Occidental International. A small force, the 18th California Volunteers Regiment, feinted north to convince the Confederates that the Americans were indeed attacking from the north as anticipated.
Order of Battle
The earliest fighting came on September 4, when the 83rd Brigade of the 42nd Division launched a full-scale attack on the Tucson Mountains, which had minimal defenses besides artillery stations at the tops of cleared peaks. The most notable encounter was in the Saguaro Range at the north end of the mountains, where a firefight ensued early in the morning in which the Confederates killed 17 Union soldiers with only one wounded on their own side to protect the western end of the Tucson Line. However, this minor victory only served to convince Craig to refortify the line, drawing cavalry units from the southern end of the valley throughout the day to reinforce the line, which came under fire from the 18th Volunteers in the early afternoon.
In the late afternoon of September 4, the 83rd Brigade had won control of the mountains and spent much of the early evening repulsing dislodged defenders. Under the cover of nightfall, Menoher ordered Capt. Walter Krueger of World War II fame to move artillery units up the mountains in preparation for the next day's attack.
September 5 saw some of the bloodiest fighting of the battle as Craig realized he had been outflanked in the mountains and sent a sizeable force, the 5th Regiment, so attack the Tucson mountains from the Saguaro Range. The diversion of forces gave the California Volunteers ample opportunity to assault the Line and dislodge the eastern end of it, albeit with heavy casualties. The 5th Arizona Regiment failed to dislodge the American positions in the higher end of the mountains and were forced to retreat in the later afternoon, but not before regrouping and launching an even bloodier second attack a few hours earlier. This gave the 85th US Brigade time to circle the mountains and attack the piecemeal, mostly militia defenses along the city's southern end and seize the tracks of the Occidental Railroad, which they tore up to prevent any trains from reaching Tucson.
By September 6, the defense American position in the Tucson Mountains was unassailable, with the 5th Regiment suffering great casualties again against minimal American casualties. The 85th Regiment moved up into the city and the Tucson Line collapsed, sinking back from their positions into the city and into the Santa Catalina mountains. Much of the city was destroyed in an ensuing artillery bombardment, with high civilian casualties. The 83rd Regiment detached a significant portion to move into the city from the west as the 85th attacked it from the south, and there was a particularly violent spate of building-to-building fighting in the late afternoon.
September 7 saw a counterattack by the Confederates aimed at pushing the American soldiers back up into the mountains, which despite early success in recapturing the Arizona Territorial Capitol and surrounding city center was repulsed, though the pursuing American soldiers suffered their worst casualties of the battle as they ran straight into a Confederate artillery bombardment, with nearly six hundred dead in the matter of three hours, the highest casualty rate of the war up until that point.
It would be the California Volunteers, led by U.S. Congressman Joseph R. Knowland, who would help dislodge the Confederates from the Santa Catalinas by attacking the remnants of the Tucson Line and securing the northern Santa Cruz valley and then clearing a path into the mountains for the 83rd Regiment as the 85th recuperated on September 8. Reinforcements soon arrived led by the 20th California Volunteers and the 1st Nevada Volunteers, who secured the central city as the 85th, moving behind the main American line, ventured up into the Rincon Mountains to outflank the Confederates.
By September 9, with the Americans quickly seizing control of the Rincons with minimal resistance, Craig elected to withdraw his remaining force from Tucson and flee east along the railroad, using railcars to expedite his journey northeast towards Santa Fe and the Army of New Mexico that was being organized there.
The battle was the first decisive victory for the United States in the war and, only a few months into the war, marked the effective end of Confederate control of the Territory of Arizona (the city of Phoenix had largely been abandoned in late August after a minimal skirmish by the Army of Arizona in order to reinforce Tucson). News of the bold tactical maneuvers of Funston and Monaher reached Washington, D.C. and was published in various newspapers, and the gallantry of the California Volunteers further increased the visibility of Congressman Knowland, who had left the capital to fight alongside his constituents and would later catapult his career as Governor of California and later President of the United States. The battle was a strategic victory for the Americans as it cut off the planned Mexican invasion of California before it ever had a chance to move past the planning stages - Confederate historians would later blame Mexican inaction for the losses in the West in the fall of 1913.
The battle did not register as profoundly in the Confederacy, where President Wilson largely dismissed it as an example of a superior American force winning a victory close to its home in a sparsely populated section of the Confederacy. The American occupation in Arizona soon led to the Arizona Brigade of Citizens (ABC, also known as the Arizona Hillboys) forming in late 1913, with the guerrilla faction becoming one of the most lethal units in the long guerrilla war between the United States and the Confederacy.