The Jupiter clay-hosted rare earth element (REE) deposit is located 60 km west of Mount Magnet, Western australia and is currently australia's largest clay-hosted REE deposit with an Inferred Resource of 1.8 billion tonnes (Bt) at 1700 ppm total rare earth oxides (TREO) at a 1000 ppm cut- off. REE mineralisation is hosted by a clay saprolite zone developed over a 40 km2 alkaline intrusion concealed by a thin layer of colluvial - alluvial sand and gravel. Microanalytical work shows REEs are mainly hosted by phosphate minerals gorceixite-goyazite-florencite, rhabdophane-monazite and xenotime, within regolith dominated by kaolinite with lesser quartz and iron (hydr)oxides, minor titanium oxides, manganese (hydr)oxides, baryte, and relict primary phases including feldspars, biotite, muscovite, amphiboles, chlorite, titanite, apatite, epidote and zircon increasing through the lower saprolite towards fresh basement. Laterite geochemistry (Geological Survey of Western australia (GSWa)) throughout the broader Jupiter region is La-Ce anomalous, the Jupiter deposit itself is a coincident magnetitic and gravity high within the regionally extensive Big Bell Suite and associated granitoids of the Murchison Domain. Two Enterprise Investment Scheme (EIS) co-funded Reverse Circulation holes were drilled to test the coincident gravity and magnetic feature in 2020, and followed up in 2023 by air Core drilling with results including 42 m at 1619 ppm TREO from 5 m. Subsequent exploration and resource definition drilling shows extensive clay-hosted REE mineralisation across the entire Jupiter geophysical feature. The underlying basement comprises a complexly zoned, strongly REE anomalous alkali intrusive complex ranging from alkali gabbro through syenodiorite, syenite to quartz monzonite and granite. REE minerals in fresh basement include bastnaesite-parisite, monazite, titanite and allanite. Chondrite-normalised REE plots of the Jupiter Intrusive Complex do not readily correspond to currently known granitoids within the Murchison Domain. This paper provides the first overview of the Jupiter deposit and its discovery, presenting the current geological interpretation, microanalytical and lithogeochemical data.