- The Mantua estate in county Roscommon came into Grace ownership in the 18th century through the marriage of Oliver Grace, a member of the Grace family of Gracefield, Queen's county (county Laois) and Mary, daughter and heiress of John Dowell of Mantua. Oliver Dowell John Grace was one of the principal lessors in the parish of Kilcolagh, barony of Frenchpark and in the parish of Shankill, barony of Roscommon, at the time of Griffith's Valuation. In 1828 he was a member of the Grand Panel of county Roscommon. The family seat was at Mantua, near Elphin. The estate amounted to over 3000 acres in the 1870s. It passed by marriage to the Bowen family of county Donegal at the end of the 19th century.
- Edward Ferguson Bowen of Burt House, county Donegal, son of John Gordon Bowen and his wife Emily Harriet Cole-Hamilton, married in 1887 Louisa Frances Grace eldest daughter and co heiress of their uncle John D. Grace of Mantua. The Bowens inherited Mantua following the death of John D. Grace in 1897.
- The Dowell estate was in the parish of Shankill, barony and county of Roscommon. In 1749 Luke Dowell was resident at Mantua. Mantua passed to the Grace family through the marriage of Mary Dowell, daughter and co heiress of John Dowell and Oliver Grace.
Grace (Co Tipperary)
- The Grace family were located in counties Kilkenny and Tipperary in the 16th century and had strong family connections with the Butler family, from whom they seem to have inherited the Brittas Castle property. In 1666 John Grace was granted the castle and lands of Brittas and 920 acres. In 1754 Henry Langley of Priestown, county Tipperary, married Margaret daughter and heiress of Oliver Grace of Brittas Castle, county Tipperary. The Langleys inherited Brittas Castle.