Government documents include the records of any official body, ranging from local to international levels. There exist a considerable number of documents from and related to Korea, although the majority of non-Korean language sources tend to focus on post-1866 affairs. The records of the U.S. Department of State or the British Foreign Office, for instance, contain many documents concerning trade, international treaties, expatriate concerns in Korea, diplomatic issues on the Asian continent, and so on.
The Yale Law Library's Country by Country Guide to Foreign Law Research highlights resources related to law in North Korea and South Korea. If your research involves international law (legal relations between nations/states), consult YLL's resources for Foreign, International, and Transnational Law.
To find the text of treaties, begin with the UN Treaty Collection.
The Foreign Relations of the United States series is an essential source for U.S. foreign affairs and diplomatic history. Produced by the State Department's Office of the Historian, FRUS is compiled from declassified documents including memos, cables, reports, and more. You can access FRUS: