Local sedimentary geology, resultant soil types and groundwater availability in the Clare Valley, which extends through the Mid-North region for 90-110 km north of Adelaide, are discussed in the context of suitability for vine-growing and quality wine production. The soils that have been mapped within the valley are divided into those formed on basement rocks and those formed on outwash sediments derived from basement rock highs. They can be acid, neutral or alkaline and loamy, clayey or sandy. There have been eleven soil zones identified in the valley, and twenty soil types. Each zone exhibits between two and five main soil types and between two and eleven minor soil types. Hence there is significant variability of soil types over a very short distance.