The Cliefden Caves is a heritage-listed geoheritage site at Mandurama, in the Central West region of New South Wales, Australia. The caves comprise Ordovician fossil localities, limestone caves, a spring and tufa dams, and a site where limestone was first discovered in inland Australia.

It has been ranked among the 70 most significant fossil sites in Australia by the Australian Heritage Council (2012) and as the thirteenth most significant limestone cave site in Australia by Davey. The site was nominated to the Register of the National Estate by the Geological Society of Australia in the late 1970s and registered in 1987. It was added to the New South Wales State Heritage Register on 30 August 2017.

The Wiradjuri language group have lived in the Lachlan River Valley, including the Clifeden Caves Area on the Belubula River. Camp sites and several scarred trees near the site provide evidence for this. Skeletal remains found in the caves document occupation from at least 6,000 years ago, however, it is likely that Aboriginal people have been living in the area for much of the 30,000 years since occupation of the Australian continent began.

The outcrop of Cliefden Caves Limestone at the junction of Limestone Creek and the Belubula River was first discovered during the explorations of surveyor George Evans on 24 May 1815 (2 years after the crossing of the Blue Mountains). A cave was recorded on the southern bank of the Belubula River as early as 1832 (Lands Department, 1832) and a map from 1883 shows the location of Bushrangers Cave, The Murder Caves and Immense Cave, apparently Main Cliefden Cave.

The first land grants, of 2460 acres each at Cliefden Springs and Cliefden, were taken up by brothers F.J. and W.M. Rothery in 1832. The barn at the homestead has bullet holes, which occurred when the Rothery family was held up by Ben Hall's gang in the 1860s.

Surveyor and leading speleologist Oliver Trickett and J. C. Wiburd, caretaker of Jenolan Caves, visited Fossil Hill and several of the caves in 1908 “in connection with their protection on the proposed resumption of the Cliefden Estate”. They described how many of the cave formations had been soiled by visitors' hands. They examined the Main Cave and reported that it was “well worth preserving”. Anderson (1924) similarly concluded that the caves were well worth preserving.

In August 1932, 1,000 specimens of cave formations were removed from the lower level of Cliefden Main Cave by the Australian Museum to create a cave exhibit in the museum. The material collected proved to be insufficient, and a further 1,000 specimens were collected in April 1934.

In the 1950s, Stevens was able to show the limestone was of Ordovician age, the first recording of limestone from this period in New South Wales. Geologists around the world regard it as a superb example of an Ordovician island faunal assemblage