Tiernan is a rare name used for both girls and boys that peaked in 2009 and has grown less common since.
Tiernan is predominantly a boy name. In 2025 it ranked #3,840 for boy births in the United States (and #8,229 across all names), given to 29 babies. Tiernan first appears in 1985 and peaked in 2007 (86 births).
| Year | U.S. births | U.S. + territories | ♀ Rank | ♂ Rank |
|---|---|---|---|---|
| 2025 | 29 | 29 | — | #3,840 |
| 2024 | 26 | 26 | — | #4,185 |
| 2023 | 35 | 35 | — | #3,408 |
| 2022 | 38 | 38 | — | #3,207 |
| 2021 | 32 | 32 | — | #3,573 |
| 2020 | 20 | 20 | — | #4,843 |
| 2019 | 24 | 24 | — | #4,320 |
| 2018 | 33 | 33 | #17,922 | #3,876 |
| 2017 | 31 | 31 | #18,223 | #4,096 |
| 2016 | 41 | 41 | #18,645 | #3,220 |
| 2015 | 51 | 51 | #18,881 | #2,678 |
| 2014 | 54 | 54 | #18,989 | #2,540 |
| 2013 | 58 | 58 | #19,063 | #2,397 |
| 2012 | 61 | 61 | #19,312 | #2,320 |
| 2011 | 80 | 80 | #14,724 | #1,923 |
| 2010 | 78 | 78 | #19,606 | #1,937 |
| 2009 | 95 | 95 | #11,396 | #1,787 |
| 2008 | 90 | 90 | #10,032 | #1,872 |
| 2007 | 91 | 91 | #20,327 | #1,738 |
| 2006 | 78 | 78 | #10,559 | #2,008 |
| 2005 | 79 | 79 | #10,863 | #1,866 |
| 2004 | 79 | 79 | #9,845 | #1,832 |
| 2003 | 75 | 75 | #8,456 | #1,904 |
| 2002 | 74 | 74 | #6,114 | #2,016 |
| 2001 | 66 | 66 | #6,597 | #2,145 |
| 2000 | 52 | 52 | #9,127 | #2,371 |
| 1999 | 48 | 48 | #10,282 | #2,339 |
| 1998 | 35 | 35 | — | #2,501 |
| 1997 | 18 | — | — | #3,865 |
| 1996 | 17 | — | — | #4,002 |
| 1995 | 21 | — | #15,585 | #4,033 |
| 1994 | 7 | — | — | #7,691 |
| 1993 | 17 | — | #15,625 | #4,965 |
| 1992 | 10 | — | — | #5,607 |
| 1991 | 13 | — | #15,274 | #6,461 |
| 1989 | 10 | — | #14,393 | #9,109 |
| 1988 | 5 | — | — | #8,396 |
| 1985 | 5 | — | — | #7,497 |