September 23 is the 266th day of the year (267th in leap years). There are 99 days remaining.
- 1956 — Brian Dugan is born.
- 1963 — George Frank Sack died.
- 1969 — William Devonshire is born.
- 1980 — Alexander Greba is born.
- 2011 — Abdelkader Salhi is apprehended.