The 1st owner of the property now known as Hibernia was George Harrison, a weaver, who lived here from as early as 1744 until he sold the land to Samuel Downing in the early 1790’s. He may have lived in the part of the mansion that was the original farmhouse. Downing built the 1st iron forge at Hibernia on the West Branch of the Brandywine to convert pig iron into bar iron. The iron works property passed through several ownerships from 1808 until 1821, when Charles Brooke purchased the property and became its most prosperous ironmaster.
By 1850, the Hibernia Iron Works, also known as Hibernia Forge, included two iron forges, two heating furnaces, a rolling mill, grist mill, the mansion, and several houses for the employed families. There was also a farm, gardens, orchards and other improvements. These all helped Hibernia become a self-sustaining operation for the Ironmaster family and hired staff, as well as for the 16 men and boys, their families, and the 18 oxen, horses, and mules which worked at producing the iron.
When Brooke conveyed the 1,594-acre property to his three sons in 1862, he did so with the understanding that he and his wife could remain in the Mansion House without charge for the rest of their lives. The Hibernia Forge operations ceased in the late 1870’s, some years after a period of management by Horace Beale.
During the 1880’s, the house was the country residence of Thomas
Costigan, a Philadelphia contractor, his wife Mary, and their family.
Costigan relished foxhunting as did the Ironmasters before him. The
Costigan family frequently used their private railroad car in traveling
between the city and Hibernia, as well as for social occasions here.
In 1894, Colonel Franklin Swayne, a successful Philadelphia real estate
lawyer, and avid foxhunter, bought the mansion and 650 acres of the
Hibernia Property. As squire of the land, he managed several enterprises
such as farming, sheep raising, and ice selling, but complained that
none were successful financial ventures. Hibernia today retains the
legacy of the gentleman’s country estate he created.
death in 1924, Swayne willed the property to his cousin, Mary Skerrett
Matteson. Although she introduced electricity to Hibernia, she used the
house primarily as a summer home for vacationing with her grandchildren.
High maintenance costs and the family’s limited use of the property
finally led her to sell Hibernia in 1963 to Chester County for the
enjoyment of all its citizens.