Santana do Livramento, locally referred to as just Livramento, is in Rio Grande do Sul, Brazil. It's on the border with Uruguay, right across from the Uruguayan city of Rivera.
Livramento's big attraction is its location on the border: Uruguayans come for the inexpensive goods on the Brazilian side, and Brazilians come for the duty-free shops on the Uruguayan side. Travellers from other countries can take advantage of both. Livramento also gives you the chance to stand with a foot in each country—a cool photo opportunity.
To a large extent, Santana and Rivera function as one city: you can easily walk from one to the other without even bringing your passport. You may not even notice you're crossing the border, which is marked by inconspicuous white border markers. If you decide to venture further into the other country, though, make sure to stop at immigration (located next to Siñeriz Shopping in Rivera) to get your passport stamped out of one country and into the other.
That being said, they are two different cities, with separate bus systems and administration and somewhat different vibes. Being in Brazil, Santana tends to be cheaper than Rivera, has more Brazilian foods and Brazilian-style buffet restaurants, and has more Portuguese than Spanish. On both sides of the border, though, it's not uncommon to have a conversation where one side is speaking Spanish and the other Portuguese, or where both sides are speaking Portuñol, a mixture of the two languages.
Access is done mainly overland, as Rivera Airport no longer operates commercial flights and the closest commercial airport is Rubem Berta International Airport (IATA: URG) in Uruguaiana, by 228 km from Santana do Livramento. Uruguaiana Airport also has just a handful of flights from Porto Alegre and seasonal flights from Florianópolis, which makes access by land easier than by air.
Porto Alegre, the state's capital, is located about 500km away, a 7h ride by bus (100-135 BRL or 30-40 USD).
From Rivera, you can just walk or drive across the border. The city is connected to other parts of Uruguay by regular bus services.
If you choose to cross the border by your own means (foot, car), you need to present yourself voluntarily at the border post located south of the city, inside a shopping mall (there's no border post on the highway). This is easy to miss as there's no clear separation between the two cities, but you'll incur fines if you later leave either country at a more rigorously controlled border crossing and they realize you didn't legally enter.
Lots of inexpensive stores catering to Uruguayans are located in the area near the border and the Praça Internacional. There are also lots of duty-free shops on the Uruguayan side.
Prices tend to be listed in reais in Livramento and in pesos in Rivera, but stores on both sides are happy to accept either currency. Currency exchange places, as well as lots of stands selling contraband, can be found on the border near the Praça Internacional. The unlicensed currency exchange stands right on the border offer very good rates, better than the official exchange places nearby. They accept US dollars as well as pesos and reais.
Cheaper hotels are available here than in Rivera.
Primary administrative division