The paper deals with the teritory of autochthonous Slovene settlement from the middle of the 19th century to the present days. On the basis of sources and statistical data on the linguistic structure of the population in Austrian Styrla, the changing of the Slovene ethnical boundary is exposed. On the grounds of the official Austrian statistics, the author treats the changes within the Slovene population and its relation to the whole populattion on the area between the years 1890—1971.