Resembling the top of a wooded knoll, it is immediately south of Herm and covers approximately 44 acres (18 ha).

There is evidence of flint manufacturing in an area exposed only at low water between the island and Crevichon which shows occupation around 10,000 BC.

[5] In 1972, Charles Hayward, founder of the Firth Cleveland Group of Companies, purchased the Crown tenancy of the island and lived there with his wife Elsie Darnell George until his death in 1983.

The British 1957 musical Free as Air by Dorothy Reynolds and Julian Slade was set on the minor and fictitious Channel Island of 'Terhou', which was based on Jethou.

Mary Gentle's 2007 novel Ilario: The Stone Golem has a villainous noblewoman exiled to a convent in Jethou.