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In the framework of a landslide inventory map of the Sierra Costa Region, we identified and classified landslides on the basis of extensive field-verified aerial photo interpretation. Geological and geomorphological data were gathered to assess the spatial distribution of the landslides, occurrence characteristics and possible associated risk. Of the 1262 landslides analysed and classified, the main geomorphological units for landslide occurrence were fluvial valleys located in the mountains (1007 landslides) and in the rolling hills (260 landslides). Debris flows were mostly controlled by lithological contacts (478 landslides) and slope gradient (367 landslides); debris slides were mainly influenced by lithological features, more specifically sedimentary rocks (208 landslides). Another significant factor was fault systems associated with fluvial valleys (92 landslides). The identification, location and classification of major mass movement types, in combination with the assessment of controlling factors, allow us to understand the nature of slope instability in the region and contribute to land planning efforts. [ABSTRACT FROM AUTHOR]