Formosa (Spanish pronunciation: [foɾˈmosa]) is the capital city of the Argentine province of Formosa, on the banks of the Paraguay River, opposite the Paraguayan town of Alberdi, about 1,200 km (746 mi) north from Buenos Aires, on National Route 11. The city has a population of about 234,000 per the 2010 census [INDEC].

Formosa is the hub of the provincial industry, that processes the product of its natural resources. The port that serves Paraguay towards the Paraná River is the main transport means for the provincial production.

Notable sights of the city include the Nuestra Señora del Carmen Cathedral, the Government House, the Torelli Botanic Forest Garden, the Provincial History Museum (Museo Histórico Provincial), the Estadio Centenario ("Centenary Stadium") football stadium, the Guaicole fauna reserve, the shore of the Paraguay River, the Isla de Oro Island, and the Central Square named after José de San Martín.

The lands were initially inhabited by the Toba and Wichí (Mataco) indigenous peoples. On April 8, 1879 Commander Luis Jorge Fontana founded the settlement that would become the capital of the National Territory of Chaco from 1884 to June 15, 1955, when it gained the status of province. The Formosa campus of the National University of the Northeast was established as the National University of Formosa in 1988.

The name of the city (and the province) comes from the archaic Spanish word fermosa (currently hermosa) meaning "beautiful". The name Vuelta Fermosa or Vuelta la Formosa was used by Spanish sailors in the 16th century to describe the area where the Paraguay River makes a turn, right in front of the actual city. These sailors were searching for the legendary Sierra de la Plata.

The city of Formosa is governed by the Municipal Council, which has autonomous status. It consists of an Executive Department (led by the Mayor), a Legislative Department (the Deliberative Council), and a Judicial Department (headed by the Municipal Chamber of Appeals and the misdemeanor judges distributed in the two Misdemeanor Courts of the city).

The Deliberative Council of Formosa has the highest number of members in the entire province, as it is the only municipality that currently has over 100,000 inhabitants in the province. There are a total of twelve councilors. The Council is headed by the President of the Council, followed by the 1st Vice President and the 2nd Vice President of the Council.

The Executive Department is led by the Mayor of the city of Formosa, who determines the members of the municipal cabinet. Within the cabinet, the Secretaries are responsible for endorsing the acts of the Mayor within their competence. Each Municipal Secretary is in charge of a specific area of the Executive Department. These secretaries, in turn, have sub-secretariats under their authority, which handle more specific competencies. Generally, the Sub-secretariats, such as the Traffic and Transportation sub-secretariat, are further divided into General Directorates, which are composed of Directorates and Departments.