Tabatinga, originally Forte de São Francisco Xavier de Tabatinga, is a municipality in the Três Fronteiras area of Western Amazonas. It is in the Brazilian state of Amazonas. Its population was 67,182 (2020) and its area is 3,225 km2. Together with the neighbouring Colombian city of Leticia and the Peruvian city of Santa Rosa de Yavari, the urban area has more than 100,000 residents spread along the Amazon River. The first Portuguese settlement in the area was founded in the 18th century as a military outpost. It became an autonomous municipality on February 1, 1983. Formerly, it was part of the municipality of Benjamin Constant. The city is the seat of the Roman Catholic Diocese of Alto Solimões. Etymology The word Tabatinga is of indigenous origin, coming from the Tupi tobatinga, having its meaning designated as white clay or soil white. It is believed that the indigenous people referred to the region with that name because of the white clay found abundantly at the bottom of the region's rivers. In the Tupi Guarani, the word also means small house. History In the middle of the 17th century, near of the Amazon River, the foundation of a village by the Jesuits was registered by the Portuguese empire. A military post and tax office were established near the site in 1766 to become a border region with Colombia and Peru. Fernando da Costa Ataíde Teives was responsible for the creation of a military post in the region and also created a border post between the domains of the Kingdom of Portugal and Spain, alongside other military posts. The town of São Francisco Xavier de Tabatinga was then established. Of the three main colonial border settlements (São Francisco Xavier de Tabatinga, Vila Ipiranga and Vila Bittencourt), only the first was actively developing. On June 28, 1866, near the village, the border between Brazil and Peru was drawn. Until then, the region was administratively subordinated to the municipality of São Paulo de Olivença, however many few municipalities were established in the region. In 1898, with the dismantling of the territory of São Paulo de Olivença and the emancipation of the district of Benjamin Constant, the city of Tabatinga became part of the newly created municipality, including it as one of the subdivisions of the main district. A post between the borders of Tabatinga and Leticia in 1924 consistently defined the borders between Brazil and