No portraits of David Thompson are known to exist. Most likenesses have been based solely on a verbal description of Thompson provided by Dr. John Bigsby after the two had met briefly in 1819. In later years, one of Thompson's daughters stated that her father had looked very similar to John Bunyan, a 17th century Christian writer and preacher. One of Thompson's grandsons described him as looking much like Joseph Curran, a prominent, 19th century Canadian lawyer and Member of Parliament. Cricket Johnston's likeness is a composite of the three references.
David Thompson mapped nearly four million square miles of North America as he traveled across Canada crossing the Rocky Mountains and on to the Pacific Ocean. He was probably the greatest mapmaker who ever lived. Because of his night observation of the Moons of Jupiter to set his chronometer, he was called Koo-Koo-Sint by the Aboriginal peoples.