Historic Structure Report
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Chapter IV:

Defense. With the advent of the Civil War, Fort Union mobilized for possible action. Because it housed an arsenal, supplies, and material, Fort Union became a prime target for the Confederate Army in the west. Fort Union was, after all, the principal supply depot for federal troops, and control of the fort meant command of its arms and materiel and command of the Santa Fe trail and communication with the States.

second Fort Union
Figure 6. The second Fort Union was an earthen fortification laid out in the shape of an eight-pointed star. This photograph was taken from the southwest in 1930. Fort Union National Monument.

Major William Chapman, commander of Fort Union, began construction of the second fort (HS-200) when the threat of the Confederates attacking the fort was imminent. The first fort, directly below the bluffs, was in an indefensible position. Chapman noted to his superiors in Santa Fe that he could construct nothing for its defense, since anything he constructed could be "commanded by higher ground in the rear and on both flanks." [1] The idea was to move the post "out of range of field pieces & small arms . . . construct an entrenched camp with bomb-proof Magazine and store houses sufficient to contain all the stores." [2] Also, Chapman planned to burn the old post before allowing it to fall into the hands of the enemy.

Earthen Fortifications. In terms of tactics, entrenchments and earthworks had well-known advantages. The function of earthworks was one of defense, with the added advantage that good troops within an earthwork could withstand an assault of three to four times as many equally good troops. Most commanding generals made their battle calculations accordingly. [3]

During the Civil War, the size of entrenchments and fortifications varied tremendously based on the time allotted for construction, the strategic location of the fortification, and the available materials. Each entrenchment had a mass or embankment covering it called a parapet. The purpose of the parapet was to "intercept the enemy's missiles, to enable the assailed to use their weapons with effect, and to present an obstacle to the enemy's progress." [4] Each fortification also had a ditch constructed with the twofold purpose of providing material for the construction of the parapet and for increasing the size of the fortification. [5] Often the top of the parapet was capped with a head log from which the men could fire. The parapet was often 10 to 15 feet of solid earth to protect against cannon fire. [6] The fortification at Fort Union was no different.

The Star Fort. [7] The construction of the fort, then, followed fairly standard contemporary army practice. When the fort was officially completed on August 26, 1861, Chapman stated that all it needed was some dressing off, and that it could be defended with 600 men. He had 1,034 troops. [8]

The plan of the fieldwork was done by Captain Cuvier Grover of the 10th Infantry. Captain Grover and Lieutenant William Nicodemus of 11th Infantry oversaw construction of the fortification. [9] Work on the fortification had progressed at a fever pitch. At one point, the army was rotating a force of 200 men—volunteers and regulars—every four hours day and night to complete the entrenchments. [10]

While the star fort was still under construction, other strategic concerns weighed on the minds of the officers of Fort Union. Military Storekeeper William Rawle Shoemaker wrote to his superiors in Washington about the gravity of the situation at the beginning of August, 1861. Shoemaker noted that they had just received word that Fort Fillmore, New Mexico with its garrison of 500 regulars, had been surrounded and taken without a fight by 300 Texans who were said to be headed next to Fort Union. Shoemaker noted that at the time there were 1,000 men at Fort Union, and two or three hundred more were expected to arrive shortly. The army, he said, would soon be putting 14 pieces of artillery in the earthwork. He noted that the earthwork was constructed a mile to the east of the first fort in the open prairie near water. Shoemaker wrote: "It is intended to get all of our (Ordnance) stores within the works and if necessary to destroy all the present buildings, and possible much property.— I will do the best I can for the preservation of the stores with the determination, however, that nothing shall fall into the hands of the enemy." [11] Women and children were removed and sent to Las Vegas or Mora shortly thereafter. [12] The length of their stay in neighboring towns did not appear in the record.

While the fortification was under construction, the various departments erected temporary storehouses in and around the star fort to protect their goods while they awaited new spaces within the bombproof structure. Storehouses were under construction at the fieldwork by September, 1861, but some perishable goods had to be kept outside under tarpaulins while construction was underway. [13] Canby in Santa Fe approved using the demilunes for storehouse construction. [14] Military Storekeeper Shoemaker wrote to the chief of ordnance in Washington that all of his stores would not fit in the earthwork, so that "we shall be obliged to erect temporary storehouses of some kind, as the other departments are doing." [15]

Apparently all of this temporary construction caused enough confusion that the department commander entered into the picture to resolve some conflicts. A letter to the commander of Fort Union from Department headquarters in Santa Fe stated that "The construction of all works of a defensive character are under the charge of the Engineer Department. . . The entrenchments at Fort Union are of that character, and all buildings, and structures of any kind within the work, or within the range of its fire are under the superintend of the officer charged with the execution of the work." [16] By October 20, 1861, work had slowed to a point where all of the men were relieved of extra duty "and work on the storehouses and barracks," and they were put back to their regular duties. [17]

Even Mr. Levi Spiegelberg, the sutler of the volunteers encamped at Fort Union at the time, began constructing buildings at the volunteer camps to serve the troops. Fort Union's commanding officer quickly forbade that situation when he noted that the structures might interfere with the line of fire from the fieldwork (which meant that Mr. Spiegelberg's buildings were probably somewhere between the first fort and the second fort). Also, the commander expected the volunteers to be moved out of Fort Union at a moment's notice, so he recommended that the sutler be ready to move with his troops. [18]

In October of 1861, troop movements out of Fort Union left the fort with so few regulars that the commander thought that all remaining stores should be moved to the fieldwork so that he would not have to split his command in case it was attacked. This meant that some of the stores remained at the first fort up until that time. [19] By January of 1862, nearly all of the quartermaster property, ordnance stores, and provisions had been moved into the fieldwork. [20]

Contemporary Descriptions. An article in Denver's Rocky Mountain News in February, 1862, described the star fort as:

. . . one of the strongest forts in the Western frontier. Its size is seven hundred and fifty feet square, parapets seven feet high. From the level of the ground on the inside with a ditch on the outside eight feet deep and fifteen feet wide. Quarters for two companies built on the insides with a large magazine, and quarters are built outside of the fort in an acute angular form from the sides of the fort, on each of the four sides with officers quarters intervening. The ordnance will be put in position early in May. Also other necessary buildings will be erected as soon as weather permits. The force at this fort is six companies numbering about three hundred men. [21]

Undoubtedly the publication of this description provided additional material for confederate military intelligence; the confederate troops, however, had been spying on the fort since August, 1861.

Contemporary with that description is one written (then later published) by one of the Colorado volunteers. In March, 1862, Ovando Hollister described the area:

Within a mile of the west side of the vale, on a gentle swell, is the fortification. A simple field-work of moderate size, with bastioned corners surrounded by dirt parapet and ditch, with a slight abatis at exposed points. The armament is poor, consisting mostly of howitzers, but the supply of ammunition is deemed sufficient for any emergency. It has bomb-proof quarters in and surrounding it forming part of the works, sufficiently large to accommodate 500 men besides the necessary room for stores. [22]

Hollister noted that he and his command were quartered in a log house below the fortification.

earthen fortification
Figure 7. This photograph shows the approximate scale of the earthen fortification as well as some aspects of its construction. This is the south angle of either HS-206 or 207, the enlisted barracks in the redans. The branches overlying the parapet retarded erosion. Log framing outlined the entrance. Fort Union National Monument.

start fort
Figure 8. This photograph of the star fort shows the deterioration of the earthwork due to erosion. The brick chimneys pierce the roof of the redan, HS-205, at fairly regular intervals. The Third Fort Union is in the background. National Archives, Still Pictures Branch.

Figure 9. The rivulets of erosion are again obvious in this photograph of the earthworks taken in 1865. The lack of sod on the structures accelerated deterioration. National Archives, Still Pictures Branch.

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Last Updated: 13-Feb-2006