Between 1902 and 1905, the U.S. Department of War spent over a half million dollars modernizing and improving the fort’s infrastructure. The Havre newspaper hailed the investment as assuring “the permanency of Fort Assinniboine.” The improvements included the 1905 construction of these three brick duplexes by Great Falls contractors Frank Coombs and Duncan Bros. The single-story buildings boast two central brick chimneys with corbeled caps, decorative exposed rafter tips, and a full-width wood-frame porch. These buildings replaced the original cavalry guardhouse built in 1887. Within, each three-room duplex featured a guard room; a room for repairing tack and saddles; and a blacksmith shop. The men who lived in the duplexes guarded horses, watched for fire, and made simple repairs. The shops were never staffed to full capacity since only four companies of cavalry were stationed at the fort from 1905 to 1907. The shops only saw about two years of use; the last cavalry troops left the post in 1907 and in 1911 the fort closed for good.