Wurdi Youang is an Aboriginal stone arrangement located off the Little River – Ripley Road at Mount Rothwell, near Little River, Victoria. The site was acquired by the Indigenous Land Corporation on 14 January 2000 and transferred to the Wathaurong Aboriginal Co-operative on 17 August 2006.
The stone arrangement takes the form of an irregular egg-shape or ovoid about 50 m (164 ft) in diameter with its major axis aligning east-west. It is composed of about 100 basalt stones, ranging from small rocks about 200 mm (8 in) in diameter to standing stones about 1 m (3 ft) high with an estimated total mass of about 23 t (23 long tons). There are three prominent waist-high stones, at its western end, which is the highest point of the ring. The purpose, use, and age of the arrangement are not known. The purpose of the site may be ceremonial in nature as with many other stone arrangements in southeastern Australia.
The site is recorded on the Victorian Aboriginal Heritage Register, the Victorian Heritage Register (H1107), and the City of Greater Geelong Planning Scheme Geritage Overlay (HO294).
A series of stones, located to the west of the arrangement's western apex, are claimed to mark the positions of the setting sun at the equinoxes and solstices. A survey study shows that these alignments are accurate to within a few degrees. Additionally, the straight sides of the arrangement, which diverge from its eastern apex, also indicate the setting position of the sun at the solstices to within a few degrees and at the equinoxes the sun sets over the three prominent stones at the apex.
It has been suggested by scientists studying the arrangements that it could be as old as 11,000 years (based on carbon dating at nearby sites), which would make it the oldest astronomical observatory in the world.
Coordinates: 37°52′30″S 144°27′28″E / 37.87500°S 144.45778°E