Ciudad del Este is the capital of Alto Paraná department, in Paraguay, situated at 25°42′S 54°63′W. Founded in 1957, it was originally called Puerto Flor de Lis, then until 1989 Puerto Presidente Stroessner (after Alfredo Stroessner). It is part of a triangle known as the Triple Frontera, or Tríplice Fronteira in Portuguese. It is linked to the Brazilian city of Foz do Iguaçu by the Friendship Bridge; Puente de la Amistad in Spanish, Ponte da Amizade in Portuguese.

It is the second largest city in the country, with a population estimated at 240,000 in the city center or 375,000 including the suburbs (Hernandarias, Presidente Franco, Minga Guazú (where the Guaraní International Airport is located).

Ciudad del Este generates about 60% of Paraguay's GDP. It is the third major free-tax commerce zone in the world, after Miami and Hong Kong, and — together with Foz do Iguaçu — it is the headquarters of the company that operates the nearby Itaipu dam. The city's economy (and Paraguay's economy as well) relies heavily of the mood of the Brazilian economy, observing that 95% of Paraguay's share of the energy generated by the Itaipu Dam is sold for Brazil (US$ 300 millions), and that daily, many Brazilians cross the border to buy less-expensive products (US$1.2 bn, mostly electronics). Smuggling is a major occupation in the city, with some estimates putting the value of this black market at five times the national economy.

The city has a large Asian-born population, specifically Taiwanese, Arabs and Iranians, evident in the city's mosque and pagodas. The Taiwanese government paid for the construction of the city's town hall in exchange for Paraguayan support in the United Nations, hence the Taiwanese flag that flies on the building.