What is hennessy last name origin?

Hennessy is an Irish surname. It is believed to have originated from the Gaelic name Ó hAonghusa, meaning "descendant of Aonghus". Aonghus was a popular given name in Ireland in early medieval times and was borne by several notable figures. The surname Hennessy is particularly associated with County Cork in southern Ireland, where it is still one of the most common surnames. Many people with the surname Hennessy have Irish ancestry and are found in other English-speaking countries such as the United States, Canada, and Australia.