RAAF Base Richmond (IATA: XRH, ICAO: YSRI) is a Royal Australian Air Force (RAAF) military air base located within the City of Hawkesbury, approximately 50 kilometres (31 mi) North-West of the Sydney Central Business District in New South Wales, Australia.

[2]: ii–iii  The base is home to the transport headquarters RAAF Air Lift Group, and its major operational formations, Nos.

Richmond is a regular venue for air shows and had at times been mooted as a site for Sydney's proposed second international airport.

Its inaugural commander was Flight Lieutenant (later Squadron Leader) Frank Lukis, who also led the base's first flying unit, No.

A military flying school was set up at the site of the present-day RAAF base on 28 August 1916, when the area was known as Ham Common.

[2]: 9  RAAF Station Richmond was established on 30 June 1925 as the fledgling service's first air base outside Victoria.

3 (Army Cooperation) Squadron, operating Airco DH.9 light bombers and Royal Aircraft Factory S.E.5 fighters, and for the next decade the commanding officer of No.

Headquarters RAAF Station Richmond was formed as a separate entity on 20 April 1936, under the command of Group Captain Adrian "King" Cole.

[2]: 113–132  As well as an Air Force base, in its pre-war days Richmond was used as a supplementary airport for Sydney; various aviation pioneers employed it in the 1930s, including Charles Kingsford Smith and Jean Batten.

[4] Commanded by Group Captain Hippolyte "Kanga" De La Rue, Richmond's combat units at the outbreak of World War II included No.

[4] On 4 September 1939, the day after Australia declared war, the base's first wartime sortie took place, a flight of three Ansons and three Seagulls patrolling the ocean off Sydney.

11 Squadron, which had disbanded in 1946, returned to Richmond in 1954 operating P-2 Neptune maritime reconnaissance aircraft, and remained until transferring to RAAF Base Edinburgh, South Australia in 1968.

[2] The base was evacuated in February 1956 due to the threat of rising floodwaters nearby, the only time in its history that flooding in the Hawkesbury region became serious enough to warrant such action.

[2]: 107–108, 116–117  The Hercules, Caribous and 707s became synonymous with disaster relief and emergency transport in Australia and the region, as well as deploying on overseas peacekeeping missions.

Richmond was the venue for many air shows including, in 1988, the largest staged in Australia to that date, celebrating the Australian Bicentenary.

[3]: 310–311 [2]: 110–111  The base also staged the RAAF's 70th Anniversary Air show in 1991, the same year that the Hercules achieved 500,000 accident-free hours of operation.

38 Squadron out of RAAF Base Townsville, were retired at the end of 2009, to be replaced by Super King Airs built by Hawker Pacific.

Initially a cadre, the squadron will expand to approximately 250 personnel by 2015, when it will begin operating the RAAF's ten C-27J Spartan transport aircraft.

[9][10] In the 1980s, RAAF Base Richmond had been strongly considered as a second international airport for Sydney, but no decision was taken at the time.

[11] In July 2012, the Federal Government decided against Richmond as a second airport, but had commissioned a study into whether the base could be employed for "limited civil operations".

[12] In September 2016 the Chief of Air Force, Air Marshal Leo Davies, stated that the RAAF favoured closing RAAF Base Richmond during the next 15 years as its functions had been declining, and the major investment in infrastructure needed to bring it to a "fighting state" could be better spent upgrading other bases.