Built in 1878 at a cost of $485, this one-story stone building is one of only two structures that date to the original fort. The 3rd Infantry Regiment arrived at Fort Missoula from Texas in November of 1877 to replace the 7th Infantry troops, temporarily garrisoned here from Fort Shaw. The men lived in tents while they first constructed their own barracks. They then built the non-commissioned officers’ quarters and this powder magazine. The solid structure, built of fieldstone quarried at McCauley’s Bluff less than a mile away, was used to store munitions while the fort was active. The dirt floor and ceiling were constructed in layers filled with sand for protection against explosion. The log non-commissioned officers’ quarters northeast of here and the powder magazine are the only standing structures original to the 1870s fort. The powder magazine survives as a striking reminder of military protection on the western frontier.