Ecuador occupies 283,561 square kilometers on the northwest coast of South America, bordered by Colombia to the north, Peru to the east and south, and the Pacific Ocean to the west. The country derives its name from its position on the equator, which crosses approximately 25 kilometers north of Quito. The nation divides into four distinct geographic regions: the Costa along the Pacific coast, the Sierra running through the Andean highlands, the Oriente covering the Amazonian lowlands east of the Andes, and the Galápagos Islands located 1,000 kilometers west in the Pacific Ocean. Despite its relatively small size, Ecuador contains more biodiversity per square kilometer than nearly any other nation on Earth, a consequence of its extreme topographic variation compressed into narrow latitudinal bands.
The Andes Mountains bisect Ecuador from north to south in two parallel cordilleras separated by a central valley. This valley, ranging from 40 to 60 kilometers wide and sitting at elevations between 2,400 and 3,000 meters, contains the bulk of Ecuador's highland population including Quito. The eastern cordillera tends toward higher elevations than the western, though both chains host numerous volcanic peaks. Geographers have counted at least 84 volcanoes in Ecuador, of which 27 show volcanic activity within the Holocene epoch. Alexander von Humboldt, traveling through Ecuador in 1802, named the central valley route the Avenue of the Volcanoes, a designation still used. The volcanic activity results from Ecuador's position on the Pacific Ring of Fire, where the Nazca Plate subducts beneath the South American Plate at approximately 65 millimeters per year.
Chimborazo, located in the western cordillera 150 kilometers south-southwest of Quito, reaches 6,263 meters above sea level, making it Ecuador's highest mountain. The peak held particular significance in early geodesic science because Earth's equatorial bulge places Chimborazo's summit farther from Earth's center than Mount Everest by approximately 2,168 meters, despite its lower elevation above sea level. French geodesic missions in 1736 and 1743 used Chimborazo and other Ecuadorian peaks to measure the shape of Earth. The mountain last erupted approximately 550 CE based on deposits analyzed in the 1990s, though vulcanologists classify it as inactive rather than extinct. Glaciers that once covered Chimborazo extensively have retreated significantly; studies published in 2020 documented that ice coverage decreased from approximately 10 square kilometers in 1962 to less than 3 square kilometers by 2016.
Cotopaxi, situated 50 kilometers south of Quito in the eastern cordillera, rises to 5,897 meters and ranks among the world's highest active volcanoes. Historical records document at least 50 eruptions since 1738, with major events in 1744, 1768, and 1877. The 1877 eruption generated lahars that traveled more than 100 kilometers down river valleys, destroying settlements and agricultural land. Cotopaxi showed renewed activity beginning in August 2015, producing ash columns reaching 2,000 meters above the crater and prompting evacuations in nearby communities. The eruption cycle continued through January 2016 before subsiding. The mountain maintains a permanent ice cap despite its equatorial location, though this glacier has diminished substantially; measurements indicate the ice volume decreased by more than 30 percent between 1976 and 2006.
The Pacific coastal region extends inland between 100 and 200 kilometers from the ocean to the western foothills of the Andes, occupying roughly one-quarter of Ecuador's total area. Elevations range from sea level to approximately 800 meters at the Andean transition zone. The Guayas River basin dominates coastal hydrology, draining an area of approximately 34,500 square kilometers and discharging into the Gulf of Guayaquil. The Guayas River itself forms from the confluence of the Daule and Babahoyo rivers near Guayaquil. Seasonal flooding historically transformed large portions of the coastal plain, though drainage projects and agricultural conversion have altered these patterns substantially since the 1960s. The northern coastal zone receives significantly more precipitation than the southern coast due to warm ocean currents and orographic effects from the low coastal mountains.
The Galápagos Islands comprise an archipelago of 13 major islands, 6 smaller islands, and more than 40 islets and rocks distributed across approximately 60,000 square kilometers of ocean. Isabela, the largest island, covers 4,670 square kilometers, while the smallest named islands measure less than one square kilometer. The islands sit on the Galápagos Platform, a submarine volcanic plateau rising from depths exceeding 3,000 meters. Volcanic activity continues, with eruptions documented on Fernandina in 1995, 2005, 2009, and 2020, and on Sierra Negra on Isabela in 2005 and 2018. The islands formed from a volcanic hotspot beneath the Nazca Plate, which moves eastward at approximately 51 millimeters per year. This movement creates an age progression, with the westernmost islands of Fernandina and Isabela being the youngest at less than 700,000 years old, while Española in the southeast dates to approximately 3.3 million years. Darwin's observations of species variation across the islands during the HMS Beagle voyage in 1835 contributed substantially to his development of evolutionary theory.
The Oriente encompasses all Ecuadorian territory east of the Andes crest, covering approximately 120,000 square kilometers of Amazonian lowland forest. Elevations decrease from approximately 1,000 meters at the Andean foothills to below 200 meters at the Peruvian border in the southeast. Major rivers including the Napo, Pastaza, and Santiago drain eastward into the Amazon system. The Napo River, Ecuador's largest Amazonian tributary, flows approximately 850 kilometers from its source on Cotopaxi's eastern slopes to its confluence with the Amazon River in Peru. Francisco de Orellana descended the Napo and Amazon in 1542, becoming the first European to navigate the Amazon from the Andes to the Atlantic. The Oriente receives between 3,000 and 4,000 millimeters of precipitation annually, distributed relatively evenly across months with a slight reduction between November and February in some areas.
Ecuador's climate varies primarily by elevation rather than season due to its equatorial position. The country experiences minimal temperature variation throughout the year, with fluctuations typically measuring less than 3 degrees Celsius between the warmest and coolest months at any given location. Daily temperature ranges often exceed annual ranges. Precipitation patterns show more seasonal variation, particularly in the highlands and on the coast. The coastal lowlands and western Andean slopes receive most precipitation between December and May, corresponding to the warmer ocean phase when the Intertropical Convergence Zone shifts southward. The dry season from June through November brings markedly reduced rainfall and cooler ocean temperatures along the coast. Guayaquil, at 4 meters elevation, averages 986 millimeters of annual precipitation, with approximately 80 percent falling between January and April.
Quito, situated at 2,850 meters in the central Andean valley, experiences a subtropical highland climate with average daily temperatures between 9 and 20 degrees Celsius throughout the year. The city receives approximately 1,200 millimeters of precipitation annually, distributed in a bimodal pattern with wetter periods from October through May and drier months in June through September. Temperature variation correlates primarily with cloud cover and time of day rather than season. Morning temperatures in Quito typically range between 8 and 10 degrees Celsius year-round, while afternoon highs reach 18 to 21 degrees Celsius regardless of month. This pattern holds across Ecuador's highland basins. Cuenca, at 2,560 meters, shows nearly identical patterns. Nighttime temperatures can drop to near freezing in highland valleys during clear-sky conditions, while daytime sun exposure at high elevation produces intense ultraviolet radiation.
The Oriente maintains consistently warm temperatures year-round, with lowland areas averaging between 24 and 27 degrees Celsius monthly. Diurnal temperature variation typically measures 8 to 12 degrees. Precipitation shows modest seasonal variation compared to western Ecuador, though most locations record slightly higher rainfall between March and July. Relative humidity remains above 80 percent throughout the year across most of the region. Cloud cover persists on most days, particularly during morning hours. The combination of high temperatures, humidity, and rainfall supports continuous forest growth without distinct dormant periods.