Ponsonby is an English surname derived from a place-name in Cumberland. The Ponsonbys were an influential family in Ireland, descended from Col. Sir John Ponsonby (1608-78), one of Cromwell's soldiers. John William Ponsonby (1781-1847) was a liberal and improving landlord. He was a popular choice for Lord Lieutenant, but his administration was overshadowed by the Great Famine. There were numerous other prominent members of the family (Oxford Companion to Irish History). Perhaps the most likely person to have inspired the name of this street, given in 1877, was Sir Henry Ponsonby (1825-95), a British general and royal court official, best known as Private Secretary to Queen Victoria. He too came from an Anglo-Irish family.