The great house and demesne had been in the French family since 1666 (when 5,000 acres were granted to Dominick French). The original manor house, built in the mid-17th century, was rebuilt in the Georgian style in the 18th century.
In the 1749, it was the residence of Arthur French II MP for County Roscommon (1728–99), Colonel of the French Park and Castlemaine Volunteers [Census of Elphin]. He was succeeded by his eldest son, Arthur French III (c1764-1820), MP for Roscommon, 1785-1820. In 1786, Wilson described French Park as "a most beautiful seat with extensive and noble demesnes".
Designed by German-born architect Richard Cassels (1690-1751) it was very similar to Strokestown House. French Park was an early Palladian winged house of Dutch red brick (of three storeys with a seven-bay centre block). Two-storey wings, five bays long and four deep, were joined to the main block by curved sweeps. Widely reputed as a building of considerable splendour, French Park also boasted beautiful gardens, orchards, and an ornamental fish-pond.
His son, Arthur French IV (1786-1856) was made the 1st Baron de Freyne, of Artagh in 1839 (aka of Coolavin). In 1837, Lewis described a massive mansion with a finely wooded dememsne of 1458 statute acres.
By 1858, Frenchpark was owned by his brother, Rev. John Ffrench, 2nd Baron de Freyne (1788-1863) and was valued at £60 [GV]. He appears on record as "The Right Hon. & Rev. Lord John de Freyne"
""Fitzstephen French M.P." aka the Right Honourable Fitzstephen French of Erritt Lodge, was a younger brother (Member of Parliament for county Roscommon and estate owner in the parish of Taghmaconnell, barony of Athlone, county Roscommon).
The 7th Baron de Freyne sold the Frenchpark estate to the Irish Land Commission in 1952, and moved to Oxfordshire. The Land Commission removed the roof of the buildings in 1953, gutted the interior, and eventually demolished the remaining structures circa 1975.
21st CENTURY RUINS
All that remains today is the historic smokehouse, still in reasonably good repair, and the ruined walls of some nearby outbuildings. The French family mausoleum stands nearby in the graveyard at Cloonshanville Dominican Priory. At Elphin Cathedral, a monument to the original Dominick French can be seen.