Dear Mr. Lee,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located 3 series, 134 file units & 36 items for Wonju and 5 items for Gangwon. For more information about these records, please contact the reference unit listed as the contact in the Catalog description. Please keep in mind that there may be additional records related to Wonju and Gangwon since the descriptions in the Catalog do not always list every geographic location mentioned in the records.
We hope this is helpful. Best of luck with your research!