Irvingtonian

The Irvingtonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 1,800,000 to 300,000 years BP. It is usually considered to overlap the Lower Pleistocene and Middle Pleistocene epochs. The Irvingtonian is preceded by the Blancan and followed by the Rancholabrean NALMA stages.

The Irvingtonian can be further divided into the substages of:
 * Cudahyan: Lower boundary source: base of Irvingtonian (approximate)
 * Sappan: Upper boundary source: base of Rancholabrean (approximate)