Mid-Joseon civil official active during the Imjin War; chief state councillor and Lord of Oseong

| Life | 1556 ~ 1618 |
| Era | 조선 |
| Clan | 경주 이씨 |
Yi Hang-bok (李恒福) had the courtesy name Jasang (子常) and the pen names Baeksa (白沙) and Pirun (弼雲). He is widely known for the "Oseong and Haneum" anecdotes of his boyhood friendship with Yi Deok-hyeong. He passed the higher civil service examination in 1580 and entered official service.
When the Imjin War broke out, he escorted King Seonjo to Uiju and, as Minister of War, oversaw military affairs, and rendered great service in diplomatic negotiations with Ming China by refuting the false charge that Joseon had colluded with Japan. For these merits he was enrolled as a first-class Hoseong merit subject and enfeoffed as Lord of Oseong (鰲城府院君). In 1600 he rose to chief state councillor.
Under Prince Gwanghae he opposed the proposal to depose Queen Dowager Inmok and was exiled to Bukcheong in Hamgyeong Province, where he died. His works include the Baeksa jip (白沙集) and the Bukcheon illok. His posthumous title was Munchung (文忠).
Geumhyeon-ri, Gasan-myeon, Pocheon, Gyeonggi Province (Gyeonggi Monument No. 24)
His descendants include Yi Gwang-jwa and Yi Tae-jwa, who served as chief state councillors under King Yeongjo, and the late-Joseon independence activist brothers Yi Hoe-yeong and Yi Si-yeong are also said to be his descendants.