The baby name Tiernan appears in baby name data for the United States from 1996 to 2023. It was most popular in 2007 with 35 babies given the name.
In the later years of this period, Tiernan has become more popular compared with earlier years.
| Year | Count |
|---|---|
| 1996 | 6 |
| 1998 | 5 |
| 2000 | 5 |
| 2001 | 5 |
| 2001 | 6 |
| 2003 | 12 |
| 2004 | 12 |
| 2005 | 6 |
| 2006 | 9 |
| 2007 | 35 |
| 2008 | 24 |
| 2009 | 31 |
| 2010 | 13 |
| 2011 | 25 |
| 2012 | 5 |
| 2013 | 10 |
| 2014 | 5 |
| 2016 | 14 |
| 2023 | 6 |