Atrato River
By the Royal Decree of February 16, 1533, the Magdalena River was set as the eastern border of Cartagena province dividing it from Santa Marta province, while the Atrato River was designated the western border. The first was governed by Pedro Fernández de Lugo, who depended on the Royal Audiencia of Santo Domingo, and the second by Pedro de Heredia, which came under the jurisdiction of the Audiencia of Panama, established in 1533.