Just west of Ecuador's capital Quito lie the Pichincha volcanoes. There are two of them, Guagua Pichincha and Rucu Pichincha. Both of them are stratovolcanoes, but while Rucu, Quechua for old man, is extinct, Guagua the baby is quite an active toddler. The mountain is famous for staging the decisive battle of Ecuador's liberation, the Battle of Pichincha, in 1822.

Rucu Pichincha is a Pleistocene volcano, 4698 metres tall at its highest. It lies closer to Quito than Guagua does, but apart from that it is peaceful and of interest only to climbers and people who like to gaze at dead volcanoes. The old man was regarded as a god watching over the kingdom of the Quitu-Cara Indians in ancient times.

The slightly taller baby Pichincha of 4784 metres has a long history of eruptions. The last magmatic one was in 1660, shortly after the Spaniards had arrived in the area, and covered Quito in a thick layer of ash. Later on only minor eruptions have occurred. However, activity started growing in 1998, and in August the following year a phreatic eruption consisting of water vapour set the nearby inhabitants on yellow alert. Earthquakes and eruptions followed in September and October, causing the closing of Quito's airports and problems of air quality, and the alert to rise to orange. Farmers in the mountainside refused to be evacuated although there was a real danger they could be overcome by mudslides or falling of ashes. However, after weeks of fear, the activity culminated in a beautiful mushroom cloud rising into a clear sky, and souvenir sellers offering photos of it a few days later.

The Pichincha province is named after the mountain. Its most important cantones in addition to Quito are Cayambe, Mejía, Pedro Moncayo, Rumiñahui, Santo Domingo, San Miguel de los Bancos and Pedro Vicente Maldonado. The Andes mountains make the eastern part of the province a highly mountainous one, while the western part is quite coastal. Although Mount Pichincha is more dominating, Cayambe is taller, at 5,790 metres. Several rivers flow through the province to the Pacific Ocean: The Guayllabamba, Blanco, Pita, Pisque and San Pedro.