Commissary Storehouse (Third Fort Union, p. 78). One of two frame sheds built perhaps in September, 1862, as Commissary Storehouses, shown on the 1866 map, described briefly in April, 1867, and June, 1868; the two structures are left off the 1868 map, suggesting that they were torn down at the end of 1868 and their removal recorded during the updating of the map. They were certainly gone by 1873, when they do not appear on a map of the Fort prepared in that year. Note that the Major A. J. Alexander letter of April 15, 1867, first says that there were three such sheds—this seems to have been an error; later in the same letter Alexander refers to "either of these warehouses," suggesting that he mistakenly wrote "three" while thinking "two". By 1868 the two buildings were being used as "grain stables" (Inspection Report, 1868, in Oliva, "Frontier Army," pp. 1048-60): "The two long frame sheds just north of the Commissary Storehouses and formerly used by that Department, have been allowed to stand and to be put to use as Stables for trains and teams just from the road. They are good sheds, in tolerable order serving a useful purpose; and would be considered at many Posts as very fair stables." HS-307 was a wooden frame structure, shown on the base map as 200 feet long and 40 feet wide; however, this size is only an estimate based on the apparent size of the building on the 1866 map and on the apparent traces on the ground, and should not be accepted without question.

Commissary Storehouse (Third Fort Union, p. 78). Built perhaps in September, 1862, as a Commissary Storehouse, but by 1868 it was being used as a "grain stable" (Inspection Report, 1868). Visible on the 1866 map, but torn down by 1868. Frame building, estimated 200 feet long and 40 feet wide. A brick chimney base was found on the south side near the east end.

Unknown. Visible on the 1866 map, but torn down by 1868. May have been an early version of the Commissary Sergeant's Quarters, later built a little northeast of this location (see HS-312, below). The structure has a stone chimney base at its west end, and was about 30 feet long by 20 feet wide. A section of fieldstone foundation can be seen along the south side of the building's outline.

Machine Shop (Third Fort Union, p. 120). This was a large enclosed yard, 200 feet square, with a machine shop building in the northeast corner. Destroyed by fire, February, 1876. Steam engine here relocated to southwest corner of Depot mechanic's corral (Third Fort Union, pp. 11-12). A good photograph of the shop in 1866 is in ill. 52, (Third Fort Union, p. 228-29); its general shape and location are shown on the maps of 1866 and 1868 (ill. 2, pp. 128-29). A plan of the shop was made in 1866, and a copy of this is on file at Fort Union National Monument (Third Fort Union, p. 120).

The Inspection Report of 1868 goes into some detail on this shop: the yard was "a sort of corral enclosure made by a low stockade," and served as a lumber yard. In the northeast corner of the yard was a large frame building, 36 feet wide east to west and 72 feet long, north to south; this was the machine shop proper. In it were a mortise machine, a jig-saw, and a tenon-machine. The building contained a "cellar," a space 12 feet wide, 40 feet long and 9 feet deep, labelled on the plan as "a basement story for shafting," and described in the 1868 report as "where the belting communicates with the flywheel." Here were a turning lathe, grindstones, and other equipment. This basement was backfilled and is not easily visible today, although in 1984 it was a clear depression, 12 feet wide and 40 feet long, filled with dark soil. Either the depression was further backfilled by the National Park Service, or sheetwash has placed more silt into and across the basement since 1984.

The machines were powered by the steam engine in a separate house. The base map shows the probable engine house; it was a structure about 26 feet long, east to west, something over 22 feet wide, north to south, and enclosed a rectangular bricked area 3 feet 4 inches wide and 7 feet long; this was probably the engine base itself. Two large flagstones are visible at the northwest and southwest corners of the engine base; their purposes are unknown. A clearly visible stone foundation is present along the north side of the building, which extended about 14 feet outside the lumberyard enclosure. The east end of the bricked area was about 24 feet west of the side of the Machine Shop itself. No evidence is visible on the ground or indicated on the 1866 plan showing how the power from the engine was carried to the basement of the Shop building.

Unknown. Mass of lime next to Machine shop. The 1866 photograph shows only a heap of lumber in this area.

Commissary Sergeant's Quarters (Third Fort Union, p. 115). Built sometime before 1883; plan on map of 1883 (ill. 5, pp. 134-35) and was in use until after 1886; possibly used until abandonment in 1891. Photograph, ill. 51 (Third Fort Union, pp. 226-27). On the ground today, the two chimney bases are easily visible. The west chimney is brick, about 3 feet east to west and 4 feet north to south. The house appears as a rectangular charcoal-stained and disturbed area with scattered artifacts; the 1883 map indicates that it was about 40 feet long and 30 feet wide. The plan of the structure shown on the base map is taken from the 1883 map of the fort. The plan shows an enclosed yard behind the building, 40 feet by 15 feet.

Smokehouse. Shown on the 1883 map (ill. 5, pp. 134-35). Fieldstone foundation that probably supported a frame or adobe structure. The foundation is one foot wide, and the building measured about 16 feet square.

Unknown. Appears to be the base of a chimney, but no known structure is indicated in this area.

Cow Stables. The plan shows a stable building about 55 feet long and 15 feet wide, with a small yard, about 25 feet by 18 feet, on its north side and a larger enclosed yard on its south, 55 feet by 30 feet (ill. 5, pp. 134-35). Today, only organic stains and disturbed earth indicate its location; some general idea of its outline can be determined from aerial photographs. Appearance of the ground indicates that most of the structure was made from "stockade," or upright posts set in holes or a continuous trench.