About 200 million years ago, the sea level receded in Southern Australia, and the overlaying sediments were eroded away, exposing the You Yangs granite as an island in a shallow sea. The granite that forms the You Yangs Ranges was originally a mass of magma that had worked its way up into the surrounding sedimentary rocks.

The name "You Yang" comes from the Aboriginal words Wurdi Youang or Ude Youang, which could have any number of meanings from "big mountain in the middle of a plain", "big or large hill", or "bald". There is a conversation that the name is being changed back to Wurdi Youang.

Matthew Flinders’ called it ‘Station Peak’ in 1802, then it was named ‘Wilanmarnartar’ in 1824 by Hamilton Hume, and ‘Mount Vilumnata’ in 1835 by John Wedge’s map, however, ‘Station Peak’ remained predominant until sometime during the 1850’s – as by the 1860’s the name ‘You Yangs’ was named.

The Yawangi Clan, the original custodians of the You Yangs, enlarged natural hollows in the rocks to form wells that held water even in dry seasons. The area around the You Yangs was called Morong-morongoo after the murnong that was abundant in that area.

Explorer Matthew Flinders was the first European to visit the You Yangs. On 1 May 1802, he and three of his men climbed to the highest point. He named it "Station Peak”, but the name was changed in 1912 to "Flinders Peak" in his honour.

References:

Clark, I. (Ed.) (2014). A Historical Geography of Tourism in Victoria, Australia. Case Studies. Berlin: De Gruyter Open. Retrieved 7 Aug. 2014, from http://www.degruyter.com/view/product/430898, p. 182.

Massola, A. (1969). journey to Aboriginal Victoria. Adelaide: Rigby Ltd. p. 11-13