Eastern Hills (Bogotá)

The Eastern Hills (Spanish: Cerros Orientales) are a chain of hills forming the eastern natural boundary of the Colombian capital Bogotá. They are part of the Altiplano Cundiboyacense, the high plateau of the Eastern Ranges of the Colombian Andes. The Eastern Hills are bordered by the Chingaza National Natural Park to the east, the Bogotá savanna to the west and north, and the Sumapaz Páramo to the south. The north-northeast to south-southwest trending mountain chain is 52 kilometres (32 mi) long and its width varies from 0.4 to 8 kilometres (0.25 to 4.97 mi). The highest hilltops rise to 3,600 metres (11,800 ft) over the western flatlands at 2,600 metres (8,500 ft). The Torca River at the border with Chía in the north, the boquerón (wide opening) Chipaque to the south and the valley of the Teusacá River to the east are the hydrographic limits of the Eastern Hills.

Geologically, the Eastern Hills are the result of the westward compression along the Bogotá Fault, that thrusted the lower Upper Cretaceous rocks of the Chipaque Formation and Guadalupe Group onto the latest Cretaceous to Eocene sequence of the Guaduas, Bogotá, Cacho and Regadera Formations. The fold and thrust belt of the Eastern Hills was produced by the Andean orogeny with the main phase of tectonic compression and uplift taking place in the Pliocene. During the Pleistocene, the Eastern Hills were covered by glaciers feeding a large paleolake (Lake Humboldt) that existed on the Bogotá savanna and is represented today by the many wetlands of Bogotá.

The main tourist attractions of the Eastern Hills of Bogotá are the Monserrate and Guadalupe Hills, the former a pilgrimage site for centuries. Other trails in the Eastern Hills follow the creeks of La Vieja, Las Delicias and others. The busy road Bogotá – La Calera crosses the Eastern Hills in the central-northern part and the highway between Bogotá and Villavicencio traverses the southernmost area of the hills. The eastern side of the Eastern Hills is part of the municipalities La Calera, Choachí, Ubaque and Chipaque.

The Eastern Hills were sparsely populated in pre-Columbian times, considered sacred by the indigenous Muisca. The native people constructed temples and shrines in the Eastern Hills and buried their dead there. The Guadalupe and Monserrate Hills, important in Muisca religion and archaeoastronomy, are the hilltops from where Sué, the Sun, rises on the December and June solstices respectively, when viewed from the present-day Bolívar Square. The construction and expansion of the Colombian capital in Spanish colonial times caused excessive deforestation of the Eastern Hills. Reforestations were executed in the 1930s and 1940s.

Large parts of the Eastern Hills are designated as a natural reserve with a variety of flora and fauna, endemic to the hills. Despite its status as a protected area, the Eastern Hills lie in an urban setting with more than ten million inhabitants and are affected by mining activities, illicit construction, stream contamination, and frequent forest fires. Several proposals to fight the environmental problems have been written in the past decades.