This geologic reconnaissance study centers on a 90 by 140 km area about 100 km southwest of Semipalatinsk near the east border of the Kazakstan Republic of the USSR. Semipalatinsk, a regional center for grain growing, and several other cities along the Irtysh River were originally established as fortified outposts by the Russians during the 18th and 19th centuries to contain the indigenous, nomadic Kazak herdsmen. The Kazakstan region remained largely undeveloped until after the 1917 Russian Revolution, when exploration geologists began discovering many large mineral deposits. Today, known resources include coal, copper, iron ore, lead, zinc, and barite; most of these are of national significance. These vast mineral resources have prompted development of many metallurgical and chemical industries in the republic. Despite the extensive exploration for mineral resources in this region, published geologic maps (Nalivkin, 1960; Esenov, 1971; Borovikov, 1972) are all at scales of 1:1,100,000 or smaller, and there are no detailed descriptions of the geology around Semipalatinsk in the open literature. Our preliminary examination of commercial remote-sensing, data indicated that the lithology and structure of this area are extremely varied and complex at all scales -- much more so than that portrayed on the published geologic maps. Therefore, the main objective of this study was to use commercially available remotely sensed data for the area and remotely sensed data obtained for analog study sites, as well as the sparse, sketchy information in the published literature, to better define and map the geologic units (Sheet 1), structure (Sheet 2), and drainage features (Sheet 3) of this area.