The history of Chuy is, above all, the history of a frontier. During the colonial centuries, the whole far east of what is today Uruguay was an undefined strip in permanent dispute between the Spanish and Portuguese empires, which fought over control of the Plata basin and the Atlantic litoral. This was one of the so-called no-man's-lands or 'neutral fields', where the boundary between the two crowns changed to the rhythm of the wars and the treaties.
The name Chuy itself comes from the stream of the same name, of indigenous root, which runs through the area and which over time would end up serving as a reference for the layout of the border between the two countries. The region was inhabited by indigenous peoples and traveled by ranchers, smugglers and soldiers of both sides, in a scene of trackers, feral cattle and troop movements.
To secure their positions, both Portuguese and Spanish built fortifications in this strategic strip. From that were born the two great fortresses that still today dominate the landscape near Chuy: the Fortress of Santa Teresa and Fuerte San Miguel, stone witnesses of that long imperial tug-of-war for control of the south of the continent.
The 18th century was the moment of greatest military tension in the Chuy area, and it left as a legacy the two fortresses that today are its greatest historical attractions. The Fortress of Santa Teresa began to be built in 1762 on the initiative of the Portuguese, who sought to secure their presence on this frontier. However, shortly after it was taken by the Spanish forces, who continued and modified its construction. The fortress, with imposing stone walls, bastions and a moat, remained one of the most remarkable colonial military works of present-day Uruguay.
A few kilometers away, Fuerte San Miguel answered the same defensive logic. Also built in the 18th century amid the Spanish-Portuguese dispute, it was placed on a rise that overlooks the wetlands extending toward Laguna Merín. Its star-shaped plan, with bastions and a moat, is typical of the fortification of the era.
Both structures changed hands according to the ebb and flow of the wars and treaties between the crowns. Over time they lost their military function and fell into abandonment, until in the 20th century they were restored and turned into historic monuments and tourist attractions. Today they let the visitor imagine the harshness of frontier life and the strategic value this corner of the continent had.
With the independence of Uruguay in 1828 and the consolidation of the Empire of Brazil, the old colonial frontier had to become a precise international boundary between two states. Over the course of the 19th century, through boundary treaties, the dividing line between the two countries was fixed in this eastern region, taking as references the Chuy stream, Laguna Merín and other geographical features.
It was in this process that the peculiarity that defines Chuy to this day was established: the boundary runs through the middle of what would later be the urban area, leaving a town split in two. On the Uruguayan side grew Chuy; on the Brazilian side, Chuí. Both developed side by side, separated only by an avenue whose central median marks the border, with no natural features in between on that stretch.
Laguna Merín, meanwhile, remained a great binational lagoon shared by both countries, with a special regime for the use of its waters and shores. The 19th-century layout thus sealed the destiny of a region that went from being a land disputed between empires to a stable border between two neighboring nations, but keeping a unique porosity and everyday coexistence.
Few places in the world embody the idea of a frontier like the twin city of Chuy (Uruguay) and Chuí (Brazil). The two towns grew against each other until they formed a single urban fabric, separated only by an avenue: the Avenida Internacional, which on the Uruguayan side is called Avenida Brasil and on the Brazilian side, Avenida Uruguai. The central median of that street is, literally, the border line: crossing the sidewalk means changing country.
This peculiarity created an intense everyday coexistence. The inhabitants of both sides mix daily to work, shop and study; two currencies circulate (the Uruguayan peso and the Brazilian real, plus the dollar) and a border 'Portuñol' that combines both languages is spoken. The 'open' border of the avenue is for that local movement; the official immigration and customs checkpoints, on the other hand, are a few kilometers away, on the highway, for those continuing on into the interior of each country.
That permeability made Chuy a case study on border regions, where the political line does not prevent a deeply integrated social and economic life. The twin city functions, in many ways, as a single bicultural and bilingual community split between two states.
During the 20th century, Chuy built its economic identity around border trade. The difference in prices, taxes and regulations between Uruguay and Brazil turned the area into a magnet for exchange, first informally and then through a formal regime of tax-free stores: the duty-free shops.
These stores, installed on the Uruguayan side, offer perfumes, drinks, electronics, chocolates, cosmetics and imported goods at attractive prices, especially for the Brazilian shoppers who cross from Chuí and southern Rio Grande do Sul. The border duty-free regime, regulated by the Uruguayan State, energized the local economy and consolidated Chuy as the great shopping center of the east of the country.
Alongside the commerce, the tourism development of the Rocha coast —with the beaches of Punta del Diablo, La Coronilla and Santa Teresa National Park— gave Chuy a role as a crossing point and base for travelers exploring the Atlantic litoral. Thus, the old land of fortresses and disputed frontiers became a city that lives off the crossing: off commerce, off tourism and off the daily coexistence between two countries that share the same avenue.