Blennerhassett family
An English and Anglo-Irish noble family with a recorded political presence in Britain and Ireland from the fourteenth century.
Last updated August 26, 2026
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Overview
The Blennerhassett family is an English and Anglo-Irish noble and gentry family whose documented history extends from medieval Cumberland into the political and landed society of England and Ireland. The family took its name from Blennerhasset, a manor in northern England, and one of its early recorded members, John de Blennerhassett, represented Carlisle in the English House of Commons in 1381 and 1384. Members of the family and their descendants continued to represent Carlisle in many Parliaments from the reign of Richard II through the early seventeenth century. In 1390, Alan de Blenerhayset obtained a grant of arms from the Crown, providing an early formal marker of the family's status. In the sixteenth century, branches of the family moved south and east within England. In 1547, the family relocated to estates at Frenze in Norfolk and Barsham in Suffolk, properties associated with former monastic lands. During the reign of Elizabeth I, the senior branch, led by Robert Blennerhassett and accompanied by his father Thomas, moved to County Kerry as part of the English settlement of Munster. This migration established the family's long-term identity as part of the Anglo-Irish landed gentry. The family's position in Ireland expanded through land grants, marriage, public office, and parliamentary representation. Under the Act of Settlement 1662, members of the family received grants covering 2,787 acres in County Kerry and 2,039 acres in County Cork. Robert Blennerhassett's marriage to Avice Conway, daughter and heiress of Edward Conway, brought the family Castle Conway at Killorglin. The estate later formed the centre of a Kerry property described as extending to approximately 7,000 acres. The family also exercised influence through representation of Tralee and County Kerry in the Irish House of Commons, constituencies in which several Blennerhassetts served as members. Other members held county offices, including that of High Sheriff of Kerry. The family's social position was reinforced by marriages with other prominent Kerry families, including the Conways, Dennys, Crosbies, Fitzmaurices, MacCarthys, O'Connells, Sealys, Springs, and Mullins. These connections linked the Blennerhassetts to wider networks of landed, political, and professional influence in the province. Through such relationships, the family was also connected to Daniel O'Connell: Jane Blennerhasset, a granddaughter of Robert Blennerhassett MP, was the grandmother of Mary O'Connell, who married him. In the nineteenth century, Rowland Blennerhassett, a lawyer and politician, was created a baronet in the Baronetage of the United Kingdom in 1809. He commemorated the family name by renaming the estate village Blennerville. Another family member, Harman Blennerhassett, emigrated to the United States in 1796. His association with the family is reflected in the names Blennerhassett Island in West Virginia and the community of Blennerhassett, West Virginia. The family also had a continuing connection with public life in modern Ireland. John Blennerhassett, an Irish politician who lived from 1930 to 2013, is identified as the most recent family member to participate in politics. The male line of the family is described as extinct in Britain. The family is therefore best understood not as a commercial brand but as a historical lineage whose significance derives from landholding, parliamentary service, aristocratic and gentry connections, and the movement of its branches between England, Ireland, and the United States.
History
The Blennerhassett family is traced to the manor of Blennerhasset in Cumberland, in northern England. The family's early political profile is associated with John de Blennerhassett, who sat for Carlisle in the English House of Commons in 1381 and 1384. Later descendants represented the same constituency through a long period extending from the reign of Richard II to that of James I. A Crown grant of arms was secured by Alan de Blenerhayset in 1390. The family moved to eastern England in 1547, establishing connections with Frenze in Norfolk and Barsham in Suffolk. During the reign of Elizabeth I, the senior branch moved to County Kerry in the context of the Plantation of Munster. Robert Blennerhassett, accompanied by his father Thomas, became established among the Anglo-Irish landed class. Robert's marriage to Avice Conway, the daughter and heiress of Edward Conway, brought Castle Conway at Killorglin into the family's possession. The property subsequently served as the centre of a substantial Kerry estate. The family's Irish landholding position was formally strengthened by the Act of Settlement 1662. Grants associated with the family covered 2,787 acres in County Kerry and 2,039 acres in County Cork. Members of the family became involved in county administration and national politics. Several represented Tralee or County Kerry in the Irish House of Commons, while others held the office of High Sheriff of Kerry. Their influence also developed through marriage alliances with a number of established Kerry families, including the Conways, Dennys, Crosbies, Fitzmaurices, MacCarthys, O'Connells, Sealys, Springs, and Mullins. The family's wider political connections included a relationship to Daniel O'Connell through Jane Blennerhasset, a granddaughter of Robert Blennerhassett MP. Jane was the grandmother of Mary O'Connell, who married Daniel O'Connell MP. This connection illustrates the family's integration into the interrelated political and landed society of nineteenth-century Ireland. In 1809, Rowland Blennerhassett, a lawyer and politician, received a baronetcy in the Baronetage of the United Kingdom. He also renamed the estate village Blennerville in honour of the family. A separate branch or family member, Harman Blennerhassett, settled in the United States in 1796. The family name was subsequently applied to Blennerhassett Island and Blennerhassett, West Virginia. The family retained a connection to Irish politics into the modern period through John Blennerhassett, an Irish politician who died in 2013 and is described as the most recent family member involved in politics. The male line is extinct in Britain. The family's historical importance rests on its transition from a Cumberland lineage to an English regional family, its establishment as an Anglo-Irish landed house in Kerry and Cork, and its sustained participation in parliamentary and county government.
- 1809
Rowland Blennerhassett receives a baronetcy
[1]Rowland Blennerhassett is created a baronet in the Baronetage of the United Kingdom and renames the estate village Blennerville.
- 1796
Harman Blennerhassett settles in the United States
[1]Harman Blennerhassett establishes himself in the United States, where places later bear the family name.
- 1662
Land grants under the Act of Settlement
[1]Family holdings in County Kerry and County Cork are associated with grants made under the Act of Settlement.
- 1547
Relocation to Norfolk and Suffolk
[1]The family relocates to Frenze in Norfolk and Barsham in Suffolk.
John de Blennerhassett represents Carlisle
[1]John de Blennerhassett is recorded as a Member of the House of Commons of England for Carlisle.
Grant of arms
[1]Alan de Blenerhayset secures a grant of arms from the Crown.
Products and positioning
Historical English and Anglo-Irish noble family associated with landed estates, parliamentary representation, public office, and regional influence in Cumberland, Norfolk, Suffolk, County Kerry, and County Cork.
Sources1 sources
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