Kediet ej Jill (Arabic: كدية الجل) is a mountain in Tiris Zemmour, Mauritania, with the city of Zouérat on its east and Fderick at west.

The mountain and its surrounding area are rich in iron deposits, thought to have been mined here since the 11th century and commercially exploited since 1952.

[1] The mountain appears bluish because of the high concentration of magnetite, an iron ore and naturally magnetic.

The vegetation includes Phoenix dactylifera, Adiantum capillus-veneris, Hyoscyamus muticus, Tamarix sp., Vachellia tortilis, Rhus tripartitus, Capparis decidua, Leptadenia pyrotechnica, Maerua crassifolia, Salvadora persica, Balanites aegyptiaca and Panicum turgidum.

[3] The site has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of crowned sandgrouse, Nubian bustards, pharaoh eagle-owls, greater hoopoe-larks, bar-tailed larks, desert larks, pale rock martins, streaked scrub-warblers, fulvous babblers, white-crowned and mourning wheatears, desert sparrows and trumpeter finches.