Mount Barker is a part of the rugged and remote Great Southern region, 360km south of Perth, Western Australia. It was famously selected as one of the first truly desirable regions implicitly suited for viticulture by John Glastone in his acclaimed work, Viticulture and Environment. Gladstone specified "the best vineyard growing environments of the Great Southern lie to the South of Mount Barker and Muirs Highway, which corresponds roughly with the 750mm rainfall isohyet" which is precisely where Terry Hogan planted the Xabregas wine estate in 1996.
Mount Barker is considered maritime influenced, unlike Frankland River for example, which is continental. As a result, the area suffers less diurnal temperature variation than the inlandregions. During growing season, Mount Barker has similar climatic conditions to Mornington Peninsular, Prosser (Washington State) and Napier (Hawkes Bay) and is significantly cooler than Clare Valley, Margaret River and Adelaide Hills, meaning these are certainly some of the coolest growing conditions on the mainland.
Xabregas vineyards are situated at the Southern end of the defined Mount Barker region, and follow the tail of the Hay River and what remains of the so-called Mount Barker Range, which remains visible from the air. Geological reports found that the Mount (of Mount Barker) is as old as the Porongurup Range, which is made of Granite. The Mount Barker Range is largely Ironstone, which is perfect ground for Riesling.