Located on the foothills of the Mount Lofty Ranges bordering the Adelaide plains, the suburb was named after Major Thomas O'Halloran, the first Police Commissioner of South Australia. O'Halloran was the second son of Major-General Sir Joseph O'Halloran. Majors Road, which runs through the suburb was also named in his honour. In pre-European times this area, along with most of the Adelaide plains, was inhabited by the Kaurna tribe. During the suburbs early years there was conflict with the local Kaurna due to their tradition of burning off scrub in the foothills to encourage game, as the fires tended to cause considerable damage to local farmland. In an official report, Major Thomas O'Halloran claimed the Kaurna also used this as a weapon against the colonists by lighting fires to deliberately destroy fences, survey pegs and to scatter livestock. Due to this regular burning, the foothills' original Stringybark forests had been largely replaced with grassland by the time the first Europeans arrived. Since the late 1960s, restrictions on subdivision and development have allowed regeneration of native trees and bush to a "natural" condition that would never have actually existed. North of Majors Road and extending into the adjacent suburbs of Trott Park and Seaview Downs is the O'Halloran Hill Recreation Park which contains walking trails through remnant bush and farm ruins. East of Main South Road is a large area of privately owned land used for horse agistment. West of South Road is of farm land and commercial vineyards now owned by the University of Adelaide. O'Halloran Hill housing is a wedge shaped division which, apart from its southern boundary with Reynella East is isolated from other suburban housing by the Glenthorne Estate and the Happy Valley Reservoir that has resulted in a relatively low crime rate in comparison to surrounding suburbs. The Glenthorne Estate was originally a farm and horse stud owned by Major Thomas O'Halloran, who lived on a property nearby named Lizard Lodge. Thomas O'Halloran was buried in a cemetery situated on the western side of South Road, and his tomb can still be found there. At the beginning of World War I the property was purchased by the Australian Army to be used as a horse stud and army remount depot. In 1947 the Federal government took over the property and established the GlenthorneCSIROResearch Station which was closed in 1998 with the property subsequently sold to the State government. In 2001 the State government handed the property to the University of Adelaide for use as a vineyard and wine research facility in partnership with BRL Hardy, the world's largest wine company. O'Halloran Hill was also the former site of the Greater Union Drive-in known as the 'Star-line' which was the only drive-in theatre to overlook the lights of Adelaide, closing on the 4th of April 1984. Next to the drive-in was the Kingston TAFE College, which closed in 2014 and the site is now occupied by the IQRA Islamic College. From 1986 to 1998 the TAFE College was also home to community radio stationCoast FM.
