It dominates New South Wales and Victoria, also extending into Tasmania, the Australian Capital Territory and Queensland.
The Lachlan Fold Belt is bordered on the west by the Delamerian Orogen from the early Palaeozoic (550 to 470 Mya).
However the original width was 2000 to 3000 km wide, with the excess size absorbed by folding and thrusting.
Most of the LFB was greatly affected by the Late Ordovician to Early Silurian Benambran Orogeny (also led to the formation of the Wagga-Omeo Zone).
The Middle Devonian Tabberabberan Orogeny affected the entire LFB and terminated the precratonic stage of its development.
This same high temperature regime produced migmatite and S-type granite from the Ordovician sediments.
Slate has been formed in other parts of the fold belt indicating intermediate pressure and low temperature.
Sediments formed on the continental shelf of the continent from this time appear in western Tasmania and north west New South Wales.
Between the continent and the island arc or trench, deep water sediments in the form of turbidites appeared in the Central Lachlan Orogen.
The Ordovician volcanoes of the arc are now found around Parkes, Wellington, Molong and east of Condobolin, Cowra and Boorowa.
All its boundaries with the Macquarie Arc are faults, indicating that this is a separate terrane, also known as the Adaminaby superterrane.
A new subduction zone dipping westwards lasted from the end of the Silurian into the Late Devonian.
Oceanic subduction (or underthrusting) is evidenced for the western and central parts by slivers of ophiolite and blueschist metamorphism.
The Narooma terrane migrated 2500 km westwards on the moving Pacific plate and became attached to the Adaminaby superterrane in Silurian times.
Conodont fossils in the Narooma Chert prove the age of the terrane to be from late Cambrian to middle Ordovician.
About 84 million years ago The Tasman Sea started to form by seafloor spreading.
This split off a segment of the coast to form the Lord Howe Rise, part of Zealandia.
Turbidites from submarine fans, trench complexes, volcanic arcs, oceanic crust and micro continents dominate lithological components.
The eastern boundary of the Western Lachlan is the Mount Wellington—Mount Useful Fault Zone (east of Melbourne).
The Adaminaby Group, from another terrane, was thrust northwards over the top of the Molong Volcanic Belt.
Sites within the Lachlan Fold Belt have been associated with economically significant production of gold, copper, silver, lead, zinc and tin.