Katherine Plunket (born as Catherine Plunket; 22 November 1820 – 14 October 1932)[1] was an Anglo-Irish aristocrat and botanical illustrator from Ballymascanlan, County Louth, a prolific Botanical illustrator and painter.,[2] the oldest person ever to be born and die in Ireland and the fourth oldest-lived Irish person in history, having lived to 111 years and 327 days.

[3] Plunket was born at Kilsaran, near Castlebellingham in County Louth, Ireland (then part of the United Kingdom, prior to the Anglo-Irish Treaty in 1921).

[2][8] Plunket was retrospectively recognised as having been the world's oldest living person after the death of Delina Filkins on 4 December 1928, when she was aged 108 years and 12 days.

[9] Plunket was included in the first-ever Guinness World Records (published in 1955), and is the only supercentenarian listed then to stand the burden of scrutiny in the years since.

She died on 14 October 1932, a month shy of her 112th birthday; her death was recorded three days later in Ravensdale, County Louth and attributed to syncope.