Seong-mo (Korean: 성모; Hanja: 聖母; lit. 'the holy mother') are female mountain deities worshipped in Korean folklore. They are also known as Sin-mo (Korean: 신모; Hanja: 神母; lit. 'the divine mother'), Mo-ju (Korean: 모주; Hanja: 母主; lit. 'the matriarch'), Hal-mi (Korean: 할미), Hal-mang (Korean: 할망), or No-go (Korean: 노고; Hanja: 老姑; all three mean lit. 'the old woman, granny, or crone').
Korean mountain deities were originally female. Only in later periods the concept of a white-bearded male mountain spirit (Sansillyeong) emerge, shifting their gender to male. The surviving legends of Seongmo can be regarded as having preserved the forms of ancient goddesses.
Japan's Yama-uba is a figure derived from an ancient female mountain deities that declined and degenerated into hags, suggesting a parallel between Korean mythology.