You can determine if the U.S. has an income tax treaty in force with another country by referring to IRS Publication 901, U.S. Tax Treaties. Additionally, you can locate a complete list and text of the current treaties on the United States Income Tax Treaties - A to Z page on the IRS website.
Sources:
Publication 901 (9/2016)
§ 894. Income affected by treaty
IRM Part 21. Customer Account Services. Chapter 8. International. Section 1. IMF International Adjustments
Publication 54 (2023)
IRM Part 3. Submission Processing. Chapter 38. International Tax Returns and Documents. Section 147. International Notices
Publication 515 (2024)
