The consolidation of Colombia as a nation-state has faced a major obstacle in the country's geography, the main topographical feature of which is the Andean mountain range. The central Cordillera of the Andes is separated from the western Cordillera by the Río Magdalena and the Río Cauca. The Pacific coastal plain that extends from Panama to the Ecuadorian frontier is covered by dense jungle, which has prevented the completion of the Pan-American Highway connection between Panama and Colombia. (In contrast, the Caribbean littoral to the north is more open and climatically better favoured.) The eastern plains - the Llanos Orientales - stretch from the foot of the eastern Cordillera south and east to the frontiers with Venezuela, Brazil, Peru and Ecuador. This fragmented landscape contains a wide diversity of altitude and relief, and since temperature depends on altitude rather than season, Colombia is, by convention, divided into ‘hot country’ (below 3,500 feet above sea-level), ‘temperate country’ (between 3,500 and 6,500 feet) and ‘cold country’ (above 6,500 feet).

The obstacles to economic development caused by poor communications can hardly be overestimated. Engineering difficulties and the high cost of construction and maintenance caused by the mountainous terrain impeded the establishment of more than a limited railway network before 1930. Indeed, Bogotá and Medellín had no direct rail connection with the Caribbean coast till the late 1950s. Thus, navigation along the Magdalena remained vital to the country's prosperity. (President Mariano Ospina Pérez in the late 1940s included the level of the Magdalena waters among the daily information that he required.)