The formation of municipalities in Rio Grande do Sul is closely related to the history of its occupation. Rio Grande do Sul began a process of territorial division based on land grants and Azorean settlement nuclei. The first division was in 1809, separating the Province of São Pedro (the former name of RS) into four big municipalities: Porto Alegre, Rio Grande, Rio Pardo and Santo Antônio da Patrulha. Since then the division was gradually intensified, reaching the current 497 municipalities.
Initially the south of the State, more densely populated, presented a bigger partition, i.e., its municipalities, when compared to those located in the northern region, presented smaller areas. Such tendency persisted until the second half of the XIX century, when the north also began to suffer a fractioning process. Provincial economy, based on livestock, was already facing a stagnation process, and the arrival of european immigrants to settle and colonize new areas was already a reality.
The immigrants settled on small farms in the valley of Taquari, Sinos and Caí rivers. Initially they devoted themselves to subsistence farming. By selling the production surplus they generated capital, what gradually led to the emergence of trade and industry. The development of such sectors gave origin to a very dynamic region, where the formation of several new nuclei took place. Population growth and excessive division of colonies, added to the arrival of new ethnical groups, resulted in the expansion of colonial areas towards the north of the State. In 1900, Rio Grande do Sul had 65 municipalities, whose majority were located at the south. Municipal emancipations were intensified year after year, reaching 232 municipalities in 1966, a number that remained steady due to federal law until the beginning of the 1980s. During that decade 100 more municipalities were formed: 11 in 1982; 29 in 1987 and 60 in 1988.
Finally, during the 1990s, other 164 municipalities were created: 94 in 1992; 40 in 1995 and 30 in 1996; summing up 497 municipalities. However, these last 30 ones were only established in 2001. Once more, the majority of these new municipalities are located north of the State, in the region of the Plateau, whereas the south remains with practically the same configuration as in the beginning of the XX century. In 2003, by injunction interposed in the Federal High Court, the municipality of Pinto Bandeira was extinguished and the State had 496 municipalities. In January 2013, due to the reintegration of the municipality of Pinto Bandeira, the State was once more formed by 497 municipalities.
Source: IBGE and SAA RS