The Unicode code point is U+20A9₩won sign (HTML: ₩).
Additionally, there is also a sign at U+FFE6￦fullwidth won sign (HTML: ￦ in the block Halfwidth and Fullwidth Forms) for use with wide fonts, especially east Asian fonts.
U+20A9₩ is not merely used in South Korea. Alternatively, the backslash (U+005C\ ) is used on Microsoft Windows and the fullwidth form (U+FFE6￦ ) is used on Mac OS. In many South Korean fonts for Windows, the backslash has the shape of the Won sign including system fonts such Gulim (굴림) and Malgun Gothic (맑은 고딕).