In 1997, an ancient iron production site, Barun-Khal 2, was discovered in the Barun-Khal valley (Olkhon region, near the west shore of Lake Baikal). This discovery initiated studies of the archaeometallurgical potential of the valley. They included magnetometry, resistivity, self-potential (SP) and radiometric surveys, archaeological excavation, analysis of chemical composition and magnetism of slag and other residuals, and radiocarbon dating of charcoal samples. As expected, the most efficient was the magnetometric survey. Despite challenging field conditions such as geology-related magnetic anomalies of large amplitude and contrast, the magnetometer survey in the Barun-Khal valley resulted in the discovery of another iron production site, Barun-Khal 3. Using the magnetometry, the general structure of the sites was studied and the places of excavation were determined. The resistivity, SP and radiometric techniques, as well as magnetic survey were useful in studying near-surface geology and recent geological history. Excavations have found well-preserved slag-tapping bloomery furnaces built into the sides of a large pit (Barun-Khal 2) or a trench (Barun-Khal 3). According to radiocarbon dating, iron production began here within the second and third centuries bc and lasted until the seventh to the eleventh centuries ad. The significance of the works in the Barun-Khal valley is determined by the fact that there exist significant gaps in the coverage of Russia (including Siberia) with archaeometallurgical studies. Most available papers on the archaeometallurgical activity in Siberia were not published in English until now. For the first time, the study of ancient iron production sites in the Olkhon region was considered as an independent scientific task and carried out using both geophysical and archaeological methods.