MARYBOROUGH, a borough, market, and post town, and the assizes town to Queen's County, in the province of Leinster, in Ireland; so called in honour of Mary queen of England, who reduced this part of the country to shire-ground by act of parliament 6 and 7 Philip and Mary. It is governed by a burgomaster and bailiffs, and has a barracks for a troop of horse. There has recently been constructed an extensive and commodious lunatic asylum. It is distant from Dublin 51 miles south-west. The population amounts to 2677. It is situated in long. 7. 20. W. and lat. 53. 0. N.