The Wikipedia has the following information about this codepoint:
Ko (Hanja: 髙|高), also variously romanized Go, Goh, or Koh, is a common Korean family name. As of the 2000 South Korean census, there were 435,000 Kos in South Korea, accounting for just under 1% of the population. Liaoyang (Hanja: 遼陽) based Go (Hanja: 高) family is The Royal of Goguryeo, Northern Yan ruler Gao Yun (Hanja: 高雲), Tang Dynasty general Gao Xianzhi (Hanja: 高仙芝) has Goguryeo origin. In South Korea, Hoengseong Go clan is also descended from the Royal dynasty of Goguryeo and the clan's genealogy book specifies Dongmyeong of Goguryeo as the direct ancestor. Japan's Koma (高麗) clan is also descendant of royal dynasty of Goguryeo. Chinese character 高麗 (Koma) originates from Goguryeo's abbreviated name (Ko'gu'ryo -> Koryo), but in Japan, 'ryo' is pronounced as 'ma'. Koryo is also the name of 10 century Korea name unified and founded by Wang dynasty, a noble family originating from Goguryeo (Koguryo), and presently known name of the country, Korea (English pronunciation of Koryo).
These Go clans in three countries are called Goguryeo Go (koguryo Ko) in common. Thus, it can be said the part 'Ko' from 'Korea' originates from the surname 'Ko', Ko(gu)ryo Dynasty surname.