Based on the recently discovered Tolmin land register from the beginning of the 16th century, the article presents the state of settlement and the population dynamics from the Middle Ages until the present of the upper Bača valley, which was settled by the Tyroleans. The historical and topographical part of the article has also taken into account a number of other land registers' or related documents (from the years 1515, 1591, 1624, etc.). With the help ofthese documents, the author has localized three until now unexplained place names from the 1377 land register: Bača, Kuk and Znojilje. For the first time in such studies, the author has given consideration to the data from the 1794 survey of houses and the 1818 population census. As the list of serfs shows, the process of acquiring surnames had not finished by 1523 (the date of origin ofthe land register), as only about 72 percent ofthe population has surnames.