This polygon shapefile contains the microregion boundaries for the state of Rondônia, Brazil, in 2001. Microregions are legally defined administrative areas in Brazil consisting of groups of municipalities bordering urban areas. Microregions are grouped together into mesoregions. In principle, Brazilian law provides for member municipalities to cooperate on matters of common interest, but in practice, these divisions are primarily used for statistical purposes by the Brazilian Institute of Geography and Statistics. This layer is part of the Evolução da divisão territorial do Brasil 1872 - 2010 dataset, a collection of data representing the evolution of Brazilian states, municipalities and cities. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.