Aguachica (Spanish pronunciation: [aɣwaˈtʃika]), is a city and municipality in the southern region of the Cesar Department, Colombia, located between the inter-Andean valley of Magdalena Medio and the Motilones. It is the second most populated municipality in the department and an important livestock and commercial center in the southeast of the Colombian Caribbean.

In terms of transportation infrastructure, its geographically strategic position connects the Colombian Caribbean with the Santanderes through the Ruta del Sol, and is also a key communication point for the Catatumbo region via National Route 70. It also has air transportation through the Hacaritama Airport, a railway system, and in parallel with the Magdalena River waterway through the port of Gamarra.

The municipality is located south of the Cesar Department, between the Cordillera Oriental Andean mountains and the Magdalena River. The municipality of Aguachica borders to the north with the municipality of La Gloria and the Department of North Santander (municipality of El Carmen); to the east with the municipality of Rio de Oro; to the south with Rio de Oro once again, with the municipality of San Martín and the Department of Santander (municipality of Puerto Wilches) and to the west with the municipality of Gamarra and the Department of Bolívar (municipality of Morales) covering a total area of 876 km², 3.8% of the total area of the Department of Cesar.

The northern area of the municipality is mountainous part of the Cordillera Oriental mountain range with altitude varying between the 200 m and 2,150 m over sea level. The southern area of the municipality of Aguachica is predominantly flat with two major rivers flowing through the region; the Magdalena River and the Lebrija River.

The territory of present-day Aguachica was inhabited by amerindian Chimila tribes, before the Spanish conquerors arrived. This tribe was later brutally decimated by the Spanish.

During the first decades of the 17th century, the area was established as the Hacienda de San Roque by the Spanish and was owned by Don Antonio Garia de Bonilla, but due to pests and illnesses the settlement was moved a few hundred meters to the south. By 1722 the settlement had grown in the middle of an hacienda predominantly owned by Don Casimiro Ramos de Barahona (also spelled Barahoja). The settlement was serving now as a rest area for merchants traveling to and from the nearby fluvial port town of Gamarra and Ocaña (present-day Department of North Santander).

On 1748, the settlement received the royal grant in favor of Jose Lazaro de Rivera and established as a Roman Catholic parish. By this time the Spanish conqueror Jose Fernando de Mier y Guerra was ordered to "pacify" the Chimila indigenous groups and to reorganize some villages in the basin of the Magdalena river. These foundations and re-foundations were approved back then by José Alfonso Pizarro viceroy of the Viceroyalty of New Granada between 1749 and 1753. In 1753 the Spanish ordered the construction of houses in Aguachica and was made part of the Government of Santa Marta.

Between 1798 and 1804 a plague swept most of the population causing the village to move to its present location. In 1914 became a municipality.