Ciudad Bolívar (Spanish pronunciation: [sjuˈðað βoˈliβaɾ]; Spanish for "Bolivar City"), formerly known as Angostura and St. Thomas de Guyana, is the capital of Venezuela's southeastern Bolívar State. It lies at the spot where the Orinoco River narrows to about 1 mile (1.6 km) in width, is the site of the first bridge across the river, and is a major riverport for the eastern regions of Venezuela.

Historic Angostura gave its name to the Congress of Angostura, to the Angostura tree, to the House of Angostura, and to Angostura bitters. Modern Ciudad Bolívar has a well-preserved historic center; a cathedral and other original colonial buildings surround the Plaza Bolívar.

Originally a Spanish settlement, it was called Santo Tomé de Guayana (Saint Thomas of Guyana). The settlement was a fortified port which had to be moved on three occasions because it was constantly attacked by Carib natives and European rivals, such as the Dutch and English. The first settlements were located downstream from Ciudad Bolívar. In 1576 Saint Thomas of Guyana was located near present-day Ciudad Guayana which is at the confluence with the Caroní River. Dutch forces led by Captain Adrian Janson destroyed the town in 1579. The second settlement was founded in 1595 by Don Antonio de Berrío, who had arrived from the New Granada with the mission of colonizing Guiana. One of Walter Raleigh's expeditions sacked the second settlement in 1617, resulting in the death of his son Watt Raleigh. Fernando de Berrio was present on March 11, 1619 in the destroyed Saint Thomas of Guyana with the credentials granted by the Royal Audience of Santa Fe, just a few months after the decapitation of Raleigh in 1618.

The first task was the reconstruction of Saint Thomas of Guyana on the sides of Chirica, a more defensible and suitable place for tobacco cultivation. Berrio commissioned Captain Jerónimo de Grados and Alonso de Monteros to recruit indigenous in the Esequibo River, but they were captured by British pirates for whose freedom they intended to collect a ransom translated into a few quintals of tobacco in branch. Finally Saint Thomas of Guyana was refounded by Fernando de Berrio in 1620.

In 1629, English and Dutch pirates, under the command of Adrian Jansz Pater, attacked and destroyed Saint Thomas of Guyana and afterwards fortified themselves in the branches and creeks of the Orinoco River.

In 1637 the Dutch, settled at the mouths of the Amakura, Essequibo and Berbice, again attacked and burned Saint Thomas of Guyana and raided Trinidad.

The fourth and present day city was officially founded in 1764 by Don Joaquin Moreno de Mendoza as San Tomas de la Nueva Guayana, Santo Tomé de Guayana de Angostura del Orinoco, or San Tomé de Angostura, named in honor of its diocese and for its position at the first narrows of the Orinoco River. The Spanish relied on trade from the Dutch colony of Essequibo further down the Caroní River until 1771.

Angostura was the capital of Guayana Province and the site of the Congress of Angostura from 1819 to 1821. It was responsible for the creation of Gran Colombia in its first year of operation. Angostura bitters were invented in the city in 1824, although the company which produced them later moved to Trinidad and Tobago.