Author of the Taengniji, a pioneer of human geography; pen names Cheongdam and Cheonghwa Sanin

| Life | 1690 ~ 1756 |
| Era | 조선 후기 |
| Clan | 여주 이씨 |
Yi Jung-hwan (1690-1756) was a late-Joseon scholar of the Yeoju Yi clan, courtesy name Hwijo, pen names Cheongdam and Cheonghwa Sanin, and a member of the Namin faction. A grandnephew-in-the-second-degree and disciple of Yi Ik, he was probably born around Gongju in Chungcheong. His father Yi Jin-hyu had been Governor of Chungcheong. He passed the 1713 supplementary civil examination and served as a Seungjeongwon clerk, Seungmunwon official, postal superintendent at Gimcheon, Seonggyungwan Jeonjeok and Minister-level secretary in the Ministry of War.
Around 1722-1725 he was entangled in the Mok Ho-ryong affair of the Sinim purge because he had lent a horse, and was interrogated four times in 1725. He pleaded innocence but, with little proof, was exiled to an island; freed in 1727 then ordered into exile again, he lost eligibility for public life. He gave up office, retreated to Gongju but never settled, wandering the country; in 1753 he received a special promotion to Tongjeong Daebu.
From records gathered over some thirty years of travel he wrote the Taengniji from around 1751; Yi Ik is said to have proofread it and written its preface and postscript. It names geography, livelihood, human character and scenery as criteria for choosing a home, emphasizes livelihood and character, and warns that factional strife damages people's dispositions.
The Bokgeo Chongnon discusses four criteria for choosing a home: geography, livelihood, people and scenery. Yi Jung-hwan especially stressed livelihood and local character, and favored places with good transport and lively exchange of goods. He is said to have noted regional products such as Jinan tobacco, Jeonju ginger and Hansan-Imcheon ramie.
The Taengniji is credited with advancing human geography and is said to have influenced Northern Learning thinkers such as Bak Je-ga. Critics note that it did not fully escape geomantic thinking and that he was bound by yangban status. Source dates for some events differ, so details need checking against original records.
He is said to be buried on Mt. Seolla in Geumcheon County, Hwanghae.