The Peake and Denison region is situated in north-central South Australia, extending from 30 to 100 miles south of Oodnadatta, along the main Northern Railway which connects Port Augusta and Alice Springs. The geology of the region is shown on the following one-mile sheets which are included with this report: Algebuckina, Nilpinna, Conway, Umbum, Boorthanna, Cadlareena and Anna. In addition, a four-mile plan was made of the area. Aerial geologic mapping was carried out in conjunction with the search for uranium and other ore deposits. Two railway trucks were used as a mobile base camp, and the camp was shifted from one railway siding to the next as mapping progressed southward. Field work was carried out from May to October, 1953, as part of the Uranium exploration programme of the Department of Mines. In addition to the writer, the following geologists participated: S.B. Dickinson, Director of Mines, L.W. Parkin, Senior Geologist, R.K. Pitman, Geologist U.S. Atomic Energy Commission, F.E. Hughes, Assistant Geologist, and B.P. Webb, Geologist. Mapping was performed on vertical air photographs, and the original compilation was made to photo scale of approximately 50 chains to the inch. Subsequently the maps were reduced to a scale of one inch to the mile for publication.