Castor is a rare boys' name that peaked in 2016 and has grown less common since.
Castor is a boy name. In 2025 it ranked #4,734 for boy births in the United States (and #10,006 across all names), given to 21 babies. Castor was first reported in SSA data in 1998 and peaked in 2016 (29 births).
| Year | U.S. births | U.S. + territories | Rank |
|---|---|---|---|
| 2025 | 21 | 21 | #4,734 |
| 2024 | 14 | 14 | #6,245 |
| 2023 | 11 | 11 | #7,363 |
| 2022 | 17 | 17 | #5,475 |
| 2021 | 17 | 17 | #5,375 |
| 2020 | 26 | 26 | #3,941 |
| 2019 | 23 | 23 | #4,353 |
| 2018 | 24 | 24 | #4,251 |
| 2017 | 14 | 14 | #6,100 |
| 2016 | 29 | 29 | #3,702 |
| 2015 | 17 | 17 | #5,336 |
| 2014 | 18 | 18 | #5,095 |
| 2013 | 17 | 17 | #5,201 |
| 2012 | 15 | 15 | #5,758 |
| 2011 | 10 | 10 | #7,598 |
| 2010 | 9 | 9 | #8,253 |
| 2009 | 13 | 13 | #6,491 |
| 2008 | 8 | 8 | #9,134 |
| 2007 | 8 | 8 | #9,046 |
| 2006 | 11 | 11 | #6,985 |
| 2005 | 9 | 9 | #7,730 |
| 2004 | 6 | 6 | #10,165 |
| 2003 | 7 | 7 | #8,802 |
| 2002 | 8 | 8 | #7,757 |
| 2001 | 9 | 9 | #7,010 |
| 2000 | 10 | 10 | #6,385 |
| 1999 | 8 | 8 | #7,247 |
| 1998 | 11 | 11 | #5,524 |