Courtesy Martie B. Lisowski Collection, Library of Congress
Ecuador is divided into three continental regions--the Costa,
Sierra, and Oriente--and one insular region--the Galápagos Islands.
The continental regions extend the length of the country from north
to south and are separated by the Andes Mountains. The Galápagos
Islands, officially called the Archipiélago de Colón, are located
1,000 kilometers west of the Ecuadorian coast within 1 south of
The Costa, located between the Pacific Ocean and the Andes
Mountains, consists of coastal lowlands, coastal mountains, and
rolling hills that separate river valleys. The widest part of the
region stretches 150 kilometers from Cabo San Lorenzo in Manabí
Province to the foothills of the Andes Mountains. In the southern
part of Guayas Province, east of the Gulf of Guayaquil, the narrow
coastal plain is only fifteen to twenty kilometers wide. The
lowlands of the Costa do not exceed 200 meters in elevation,
whereas the coastal mountains extend no higher than 1,000 meters.
The coastal mountain chain, known as the Cordillera Costañera,
divides the region into the Costa Externa, next to the coast, and
the Costa Internal, next to the Andes. The Cordillera Costañera
reaches from Esmeraldas in the north to Guayaquil in the south.
North of Portoviejo in Manabí Province, the Cordillera Costañera
loses its character as a mountain chain and becomes a series of
hills and small mountains.
The Sierra consists of two major chains of the Andes mountains,
known as the Cordillera Occidental (Western Chain) and Cordillera
Oriental (Eastern Chain), and the intermontane basin or plateau
between the two chains. Several transversal mountain spurs, known
as nudos, cut across the plateau. The Nudo del Azuay, at
4,500 meters the highest of these transversal spurs, divides the
Sierra into two subregions--the area of modern volcanism to the
north and the area of ancient volcanism to the south. The former
area consists of newer, higher mountains than those in the ancient
volcanism section, which with time have eroded to lower levels.
The Sierra has at least twenty-two peaks over 4,200 meters in
height. Of the two cordilleras, the Cordillera Oriental is wider
and generally higher, with peaks averaging over 4,000 meters. The
Cordillera Occidental, however, contains the highest point in
Ecuador, which is the Mount Chimborazo at 6,267 meters. The Sierra
also contains the highest point on the equator, Mount Cayambe at
The Sierra has at least thirty peaks of volcanic origin,
including six still active. These peaks, which vary in width from
80 to 130 kilometers, are located in the area of modern volcanism
known as the Avenue of the Volcanos. The most active volcano is
Mount Sangay, 5,230 meters high. Although its last major outpouring
of lava occurred in 1946, specialists consider Mount Sangay to be
in a constant state of eruption because of fires and bubbling lava
at its crater. Mount Cotopaxi, at 5,897 meters the highest active
volcano in the world, last erupted in 1877 and is now listed as
"steaming." Its crater is 800 meters in diameter. In addition to
the other damage caused by eruptions, volcanos in the Sierra have
melted snowcaps, which in turn generate massive mudslides and
avalanches. Earthquakes and tremors also are common in the region.
The intermontane plateau between the two cordilleras is divided
by the nudos into roughly 10 basins, or hoyas, that
range from 2,000 to 3,000 meters in altitude. The average altitude
of the plateau is 2,650 meters.
The Oriente to the east of the Cordillera Oriental consists of
two subregions: the Andean piedmont and the Eastern lowlands. The
piedmont drops from a height of 3,353 meters to the featureless
lowlands, which spread out at an altitude of 150 to 300 meters.
The Galápagos Islands consist of a chain of large, medium, and
small islands that have a combined area of roughly 8,000 square
kilometers. The largest island is Isabela Island, also known as
Albemarle Island, which is 120 kilometers long with an area of
4,275 square kilometers. All of the islands are of volcanic origin,
and some have active cones. Santo Tomás, located on Isabela Island,
is the highest peak of the Galápagos at 1,490 meters. Its crater is
ten kilometers in diameter.
Data as of 1989