Colina vs. cerro vs. monte
The Spanish language has a rich vocabulary for describing geographical features. Although 'colina', 'cerro', and 'monte' all refer to elevations in the landscape, there are subtle differences in meaning and usage that can be understood through diverse examples.
Colina
A 'colina' is generally used to describe a small hill, typically one that is smooth or softly sloping.
La casa está en lo alto de una colina.
(The house is at the top of a hill.)
Subimos la colina para tener una panorámica del paisaje.
(We climbed the hill to have a panoramic view of the landscape.)
Cerro
'Cerro' is often used to describe a somewhat steeper or more rugged hill.
El cerro es muy empinado y difícil de trepar.
(The hill is very steep and difficult to climb.)
La ciudad está rodeada de cerros.
(The city is surrounded by hills.)
Monte
'Monte' can refer to either a hill or a mountain, but is often used more broadly to mean wilderness or wild undeveloped land, especially if it's wooded.
El monte está lleno de árboles y animales salvajes.
(The wilderness is full of trees and wild animals.)
Vivimos al pie del monte.
(We live at the foot of the hill.)
Summary
Although that 'colina', 'cerro', and 'monte' may each be translated as ‘hill’ in English, there are nuanced differences in their meanings. The term 'colina' tends to refer to smaller, smoother hills; 'cerro' to steeper or more rugged terrain; and 'monte' can denote either a hill or mountain - or, more broadly, wild undeveloped land, particularly if wooded.