Sir Richard Graves MacDonnell KCMG CB (Chinese: 麥當奴; 3 September 1814 – 5 February 1881) was an Anglo-Irish lawyer, judge and colonial governor.

[3] In 1852, (when he was also gazetted Companion of the Order of the Bath) he was nominated as Lieutenant Governor of St. Lucia, but without taking up the post he was sent, 10 January 1853, to become administrator and Captain General of the island of St. Vincent.

Described as a 'dominant personality' and having gained a reputation for forthrightness and intolerance, MacDonnell was appointed the sixth Governor of South Australia, arriving 9 June 1855, taking over from Boyle Travers Finniss who had been acting since the departure of Sir Henry Young.

He extended railway and telegraph communications within the colony and opened up valuable copper mines on the Yorke Peninsula, while increasing the progress in agricultural and pastoral pursuits.

He maintained that Charles Sturt and Edward John Eyre were overrated as explorers as they seemed "generally to have a knack of getting into the most dismal places and finding barrenness from Dan to Beersheba".

As a patron of South Australian culture he encouraged students who could not travel abroad to continue their post-primary schooling, and with his customary dash personally examined candidates and donated prizes, but his plan collapsed after he left the colony.

During his tenure, MacDonnell developed Victoria Peak, which would eventually become the premier residential quarters in Hong Kong, accessible only to rich European merchants.

Finally, MacDonnell's administration was marred by a huge budget deficit, which resulted in the government asking the The Hongkong and Shanghai Banking Corporation for a financial aid package.

The administration was also damaged by the actions of the Canton Customs agency, who patrolled the waters off Hong Kong and boarded ships to search for smuggled goods.

In 1847, MacDonnell married Blanche Ann, daughter of Francis Skurray of Beckington, Somerset, who lived at Stanhope Place, Hyde Park and Percy Cross Lodge, Fulham, before retiring to 5 Brunswick Square, Brighton.