To market house, or shambles as they were known, was erected on the south side c. 1825 by Mount-Sandford. It is gable-fronted to the square and has an oculus in the gable. Incised name plaque with hood and brackets above the entrance reads "Castlerea Market." This handsome and simply articulated structure still retains an air of its former use. Market houses are a notable feature of many Irish towns with varying styles of architecture, size and ornamentation. They are usually located at the centre of the town at which at one stage a market was held, with a covered arcade to protect traders from the elements and allow access for carts, animals and produce. Located opposite the entrance to the former Castlerea House, this market house is prominently located and socially significant within the town.