The two long two-storey blocks, each fourteen bays wide and separated by design to keep men and women apart, were built around 1860 to the standard plans of George Wilkinson, the architect who worked for the Poor Law Commissioners across Ireland. That separation of the sexes was not incidental; it was one of the deliberate indignities of the workhouse system, breaking up families as a condition of relief. What is unusual here is that the original layout has largely survived, and the buildings now serve as Saint Jarlath's School, making classrooms of what were once wards.

The Mountbellew Poor Law Union was formally declared in 1850, and the workhouse that followed was costed at £5,150 for construction, with a further £920 for fittings, and was designed to hold 500 inmates. A fever hospital and a chapel were part of the original complex, though both have since been demolished. The main blocks endured, and when the property was advertised for sale in 1931, the Galway Vocational Education Committee took out a 99-year lease. The workhouse reopened in 1932 as one of the first vocational schools in the country, a quietly significant transition given how new that model of technical and practical secondary education was in Ireland at the time. The fabric of the place reflects both eras: roughcast rendered walls, limestone surrounds to the doorways, cast-iron rainwater goods, and gate piers decorated with trefoil motifs and fleur-de-lys ironwork that sit oddly decorative against the institutional plainness of the blocks themselves. The former dining hall, a three-bay gable-fronted structure connecting the two main blocks, still carries a bellcote on its gable, a small ecclesiastical flourish that now marks what was once the most regimented room in the building.