Geoffrey Thomas Thistlethwaite (also spelt as Jeffrey or Geffray; also spelt as Thislthwaite; 1602 – August 24, 1683) was the 11th great-grandfather of Cometan, classified as one of Cometan’s distant paternal ancestors in the McKerney family line. Born in Dent, Yorkshire (in modern-day Cumbria), Geoffrey is understood to have been the son of Richard Thistlethwaite (1570 – 1619) and Jane Hall (1570 – 1620). Geoffrey was the husband of Jane Burton (1607 – 1691) and is thought to have been the father of Philip Thistlethwaite (1629 – 1710). Geoffrey is understood to have married his wife Jane on 6th July 1628 in Dent, likely at St Andrew’s Church.
In Cometanic ancestry, Geoffrey is categorised as part of the 13th generation retrograde, classifying him as a distant ancestor of Cometan.