Sao Borja was the first of the Sete Povos das Missoes, the Seven Peoples of the Missions, a network of Jesuit settlements built among the Guarani in the late seventeenth century. Founded in 1682, it was named Sao Francisco de Borja in honor of Saint Francis Borgia, a Spanish nobleman who became a leader of the Jesuit order. These missions were self-governing Christian-indigenous communities, prosperous and orderly, until the political quarrels of Portugal and Spain tore them apart in the following century. Sao Borja outlived the collapse of the mission world and grew into a town, carrying the deepest roots of any municipality in the state.

Sao Borja is known across Brazil as the Terra dos Presidentes, the Land of the Presidents, and it has earned the title. Two heads of state were born here. Getulio Vargas, born in 1882, dominated Brazilian politics for a generation, ruling through the 1930s and 1940s and again in the early 1950s before his presidency ended in his suicide in 1954. Joao Goulart, born in 1919 and known as Jango, rose under Vargas's mentorship to the presidency himself, only to be overthrown by a military coup in 1964. That a frontier town of the deep interior should produce two presidents is a quirk of history the city celebrates with statues and memorials.

Geography made Sao Borja a gateway. The Uruguay River, which the Portuguese spell Uruguai, defines the international boundary here, and on the Argentine side sits the city of Santo Tome. The two are joined by the Integration Bridge, a span whose very name speaks to the easy traffic of people and trade across this frontier. Sao Borja has its own airport, and the town has long served as a crossing point where Brazil and Argentina meet. The river that once marked the contested edge of two colonial empires now stitches two nations together, and the bridge carries the everyday business of a living border.

To visit Sao Borja is to feel the layers of South American history compressed into a single town. The Guarani and the Jesuits who built the first mission, the soldiers and surveyors of the imperial frontier, the two presidents whose careers reshaped a republic, all of it began here on the banks of the Uruguay. The town is quieter now than its outsized history might suggest, a place of cattle country and river light. But its claim to being both the oldest municipality in the state and the cradle of national leaders gives Sao Borja a gravity that lingers in its plazas and along its riverfront.