The Tritton-Girilambone copper (+gold) district hosts the Tritton and Murrawombie mines, completed mines at Larsens and North-East, and undeveloped deposits at Avoca Tank, Budgery, Budgerygar and Kurrajong. The total contained copper metal in the combined deposits is in excess of 750,000 t; and exploration prospectivity remains significant.Host-rocks to copper mineralisation are Ordovician in age and these rocks have been deformed during the Benambran Orogeny and younger deformation episodes, resulting in complex overprinting relationships. Despite this, a consistent structural history, derived from recognised ductile deformation features, has been established across the Tritton-Girilambone district. While a volcanic-associated massive sulphide (VAMS) genetic model has been proposed (Gilmore et al., 2015), hydrothermal activity manifested as alteration and sulfide mineralisation, and occupied a discrete period within the structural history. The mineralisation is herein considered to be of an orogenic Cu style, with implications for exploration for these deposits in the broader district. CITATION: Murphy, T and Cox, B, 2019. Development in understanding of the Tritton-Girilambone Cu district, Australia: resolving hydrothermal mineralisation in multiply-deformed rocks, in Proceedings PACRIM 2019, pp 237239 (The Australasian Institute of Mining and Metallurgy: Melbourne).