Rionegro is a city and municipality located in the Eastern Antioquia subregion of Antioquia Department, Colombia. Its official name is Ciudad Santiago de Arma de Rionegro. The city derives its name from the Río Negro (Black River), which runs through it and is the municipality's most prominent geographical feature. The river appears dark due to shadows cast by overhanging trees along its course.
Rionegro holds significant historical importance in Colombian history. It is sometimes called the "Cuna de la democracia" (Cradle of Democracy) because of its prominent role during Colombia's independence struggle. The city served as the location where the Colombian Constitution of 1863 was written, cementing its place as a center of political and democratic development during a formative period in the nation's history.