This article examines how Korean geomancy evolved over a thousand years, from the early tenth century through the first half of the twentieth. Theories and practices that emerged over the years effectively reveal Korean geomancy’s uniqueness. Such uniqueness prompts us to examine Korean geomancy during three periods, as geomantic theories and practices in any one of these three periods certainly differed from the other two. The first period began in the tenth century when Koryŏ geomancy was actually formed. The state of Koryŏ monopolized control of geomantic knowledge by tying it into the political and religious authority of Wang Kŏn, the founder of the Koryŏ Dynasty. And in terms of content, Koryŏ geomancy also merged with Buddhism and cults of the mountains and rivers. The second period began in the fifteenth century, when Korean geomancy went through certain theoretical transformations, while its social implications also changed under the newly established Chosŏn Dynasty. As the authority of Wang Kŏn was lost and the political authority of Cheng-Zhu Neo-Confucian ideology grew dominant, Buddhism and geomancy lost their prior footholds in the political arena. Existing geomantic texts were replaced with new ones, which fit well the Neo-Confucian view of nature. The third began in the seventeenth century when Chosŏn society was still suffering the aftermath of both the Imjin War (the Japanese invasion from 1592–1598) and Pyŏngja War (the second Manchu invasion of 1636). During this period, various kinds of geomantic prophecies continued to circulate, and the geomantic practice of searching out places suitable for hermitages or residences was established as a mainstream trend. Meanwhile, as clan organizations formed and a patrilineal kinship system was being firmly established, theories regarding ŭmt’aek p’ungsu gained popularity because they promised the location of auspicious sites for ancestral graves. Characteristics of Korean geomancy may be summarized as follows: First, in the early period, geomancy merged with other belief systems and also served as a political ideology. Instead of standing on its own, it later merged with Buddhism and Neo-Confucianism. Second, geomancy served as a discourse that facilitated land development. Third, geomancy was closely connected with the family system of the time, as well as the practice of ŭmt’aek p’ungsu.