Brennen is an uncommon variant of Brennan that peaked in 2009 and has since faded.
Brennen is predominantly a boy name. In 2025 it ranked #4,882 for boy births in the United States (and #10,335 across all names), given to 20 babies. Brennen first appears in 1962 and peaked in 2009 (455 births).
| Year | U.S. births | U.S. + territories | ♀ Rank | ♂ Rank |
|---|---|---|---|---|
| 2025 | 20 | 20 | — | #4,882 |
| 2024 | 31 | 31 | — | #3,623 |
| 2023 | 34 | 34 | — | #3,428 |
| 2022 | 39 | 39 | — | #3,110 |
| 2021 | 53 | 53 | — | #2,507 |
| 2020 | 57 | 57 | — | #2,350 |
| 2019 | 74 | 74 | — | #1,977 |
| 2018 | 65 | 65 | — | #2,148 |
| 2017 | 88 | 88 | — | #1,749 |
| 2016 | 126 | 126 | — | #1,391 |
| 2015 | 143 | 143 | — | #1,261 |
| 2014 | 158 | 158 | #17,005 | #1,202 |
| 2013 | 198 | 198 | #14,932 | #1,014 |
| 2012 | 302 | 302 | — | #757 |
| 2011 | 306 | 306 | — | #740 |
| 2010 | 392 | 392 | #17,476 | #629 |
| 2009 | 464 | 464 | #11,622 | #580 |
| 2008 | 383 | 383 | #12,782 | #650 |
| 2007 | 383 | 383 | #7,445 | #654 |
| 2006 | 304 | 304 | #9,388 | #732 |
| 2005 | 326 | 326 | — | #659 |
| 2004 | 344 | 344 | #12,986 | #627 |
| 2003 | 406 | 406 | #14,137 | #560 |
| 2002 | 372 | 372 | #15,821 | #583 |
| 2001 | 372 | 372 | #9,472 | #571 |
| 2000 | 390 | 390 | #13,412 | #549 |
| 1999 | 348 | 348 | #11,558 | #574 |
| 1998 | 387 | 387 | #9,379 | #534 |
| 1997 | 322 | — | — | #575 |
| 1996 | 259 | — | #13,819 | #656 |
| 1995 | 259 | — | #8,871 | #661 |
| 1994 | 242 | — | — | #668 |
| 1993 | 190 | — | #13,739 | #771 |
| 1992 | 187 | — | #10,624 | #779 |
| 1991 | 170 | — | #7,495 | #819 |
| 1990 | 139 | — | #9,357 | #900 |
| 1989 | 135 | — | — | #864 |
| 1988 | 123 | — | — | #857 |
| 1987 | 93 | — | — | #983 |
| 1986 | 60 | — | — | #1,243 |
| 1985 | 59 | — | #10,859 | #1,305 |
| 1984 | 51 | — | — | #1,297 |
| 1983 | 43 | — | #9,152 | #1,600 |
| 1982 | 50 | — | #10,679 | #1,419 |
| 1981 | 21 | — | — | #2,351 |
| 1980 | 36 | — | — | #1,624 |
| 1979 | 27 | — | — | #1,947 |
| 1978 | 17 | — | — | #2,581 |
| 1977 | 26 | — | — | #1,912 |
| 1976 | 22 | — | #9,447 | #2,518 |
| 1975 | 24 | — | — | #1,953 |
| 1974 | 12 | — | — | #2,971 |
| 1973 | 7 | — | — | #4,105 |
| 1972 | 8 | — | — | #3,659 |
| 1971 | 11 | — | — | #2,992 |
| 1970 | 17 | — | — | #2,222 |
| 1969 | 8 | — | — | #3,342 |
| 1968 | 9 | — | — | #2,931 |
| 1966 | 7 | — | — | #3,275 |
| 1965 | 7 | — | — | #3,271 |
| 1963 | 5 | — | — | #4,105 |
| 1962 | 6 | — | — | #3,676 |