The Pacho Formation (Spanish: Limolitas de Pacho, Kslp) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes.

The formation consisting of alternating siltstones and shales with siderite concretions dates to the Middle Cretaceous period; Late Albian to Cenomanian epochs and has an approximate thickness of 1,050 metres (3,440 ft).

The formation was defined and named in 1982 by Ulloa after Pacho, Cundinamarca.

[1] The Pacho Formation has an approximate thickness of 1,050 metres (3,440 ft), and is characterised by a sequence of alternating siltstones and shales with siderite concretions.

The formation has been deposited in an outer marine platform environment.