Upvote:1
If you're transiting through South Korea on the way to the United States, you don't need a visa provided you stay within the sterile area of the airport and leave within 24 hours.
Per South Korea's visa rules for tourists, before COVID you actually had the option to enter the country for up to 30 days if you were transiting to the U.S. and held a U.S. visa, but this has been and remains suspended.