The Mills Cross Telescope was a two-dimensional radio telescope built by Bernard Mills in 1954 at the Fleurs field station of the Australian Commonwealth Scientific and Industrial Research Organisation in the area known now as Badgerys Creek, about 40 km west of Sydney, New South Wales, Australia.
Each arm of the cross was 1500 feet (450 m) long, running N–S and E–W, and produced a fan beam in the sky.
Between 1954 and 1957, Bernard Mills, Eric R. Hill and O. Bruce Slee, using the Mills Cross, carried out a detailed survey of the sky and recorded over 2,000 sources of discrete radio emission, publishing results in a series of research papers in the Australian Journal of Physics.
Two of the old 13.7m dish antennas were relocated from the University of Sydney site to the CSIRO at Marsfield in 2005, as part of a precursor study into the Square Kilometer Array (SKA) development.
Other large cross-type radio telescopes were later built in the United States, Italy, Russia, and Ukraine.