The border area in Brazil was defined, for the first time, as a delimited geographical area during the imperial period, through law 601, 18 of September 1890. Since then, the region has undergone several territorial transformations. This article aims to analyze the territorial transformations and densification of the municipal grid in the Brazilian border range from 1872 to 2010. For the analysis of the year 1872 was used the population base of Cedeplar and for 1900 to 2010 the territorial division used IBGE. The results indicate that the border strip gained new territories derived from border litigation processes with neighboring countries, there was change in the width of the border strip that were initially 66 km, then became 100 km and later 150 km and the formation of municipalities was derived from a few "mother-territories". The process of densification of the municipal grid in the border area was exponential and rapid. The periods of greatest municipal creation were between 1960 and 1970 and between 1991 and 2000 with the emergence of 281 new municipalities that represent 47% of the current total.