In this article, spatial autocorrelation and its selected local indicators are discussed, while the indicator of the first written mention concerning municipalities of the Slovak Republic is particularly studied. Knowledge and interpretation of this phenomenon represents an initial precondition of an extensive analysis and application of spatial autocorrelation in research as well. In the empirical part of this paper the overall benefit of the method used in geographical research by application of the first written mention of a municipality along with the aim of identifying historically settled regions of Slovakia will be emphasized. In order to understand the identified historical regions, an insight into the issue of historical stages of the settlement development of Slovakia was necessary. An attempt was made to substantiate the arguments and knowledge with research results reached in this field.