The Une Formation (Spanish: Formación Une, Kiu) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes.

The predominantly sandstone formation dates to the Middle Cretaceous period; Albian to Cenomanian epochs and has a maximum thickness of 1,100 metres (3,600 ft).

[1] The Une Formation has a maximum thickness of 1,100 metres (3,600 ft) and is characterised by a sequence of sandstones.

[2] Fossils of Heminautilus etheringtoni have been found in the Une Formation.

[4] The Une Formation is apart from its type locality, found on the Sumapaz Páramo.