This one-story, hipped-roof building presented an attractive residential front with a graceful dormer and full-length front porch supported by Tuscan columns, but its rear, with small arched barred windows and nineteen-inch-thick exterior walls, showed that it was built to house the fort’s prisoners. Completed in 1905 by contractors Frank Coombs and Duncan Brothers of Great Falls for $23,555, it replaced a smaller guard house as a well-detailed, state-of-the-art facility. Its large cellblock could hold up to fifty prisoners, who usually served thirty-day sentences for offenses such as drunken behavior, insubordination, and going AWOL, or absent without leave. During the day, prisoners worked outside in chain gangs, and at night they slept on the floor because no beds or mattresses were provided, though they were allowed to bring blankets. After the fort closed, the Army donated the building to Havre for use as a jail, but transporting it proved impractical, and the city instead reused the cell bars before returning them years later after construction of Havre’s current correctional facility.