The Chilgog Formation (Korean: 칠곡층; Hanja: 漆谷層; RR: Chilgok-cheung), also known as the Chilgok Formation, is an Early Cretaceous geologic formation in South Korea.

[1] Formerly dated to the Berriasian to Hauterivian, later dating has established an Albian age.

[2] Dinosaur remains, possibly of sauropods,[3] are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.

[4] The formation predominantly consists of sandstone, mudstone and conglomerate, with subordinate tuff and other volcanics.

[5] It overlies the Jinju Formation and underlies the Silla Conglomerate, which underlies the Haman Formation, respectively.