Practically, the unofficial world record is now limited today to swimmers competing in the United States, as short course races in yards are only currently used for record keeping in the United States.
The list of United States records in swimming includes records in short course yards, including the "USA record", meaning the fastest time by an American swimmer, and the "US Open record", meaning the fastest time within the United States.
The vast majority of records in the 50 yard freestyle in the past 80 years have been set at U.S. collegiate competition.
[1] Interim records between those records reported in this list may exist and merit addition if supported by reliable sources.
By the time Duke Kahanamoku swam 22.6 in 1923, the level of certainty in the progression of this list improves.