Isabel Thistlethwaite (also spelt as Isabell; née Willan; ???? – 1730) was the 9th great-grandmother of Cometan, classified as one of Cometan’s distant paternal ancestors in the McKerney family line.
Isabel married Thomas Thistlethwaite on 20th April 1713 in Dent, York and she gave birth to at least one son named Christopher, but there is confusion as Christopher’s date of birth is 1709 which would mean Isabel had her son out of wedlock which would have been unlikely for the 18th century. Isabel’s death is recorded as having occurred in Dent, Yorkshire in 1730. Isabel was the daughter of James Willan (1653 – 1717) and Lucy Bland (1660 – 1732).
In Cometanic ancestry, Isabel is categorised as part of the 11th generation retrograde, classifying her as a distant ancestor of Cometan.