Brennan is a distinctive girls' name in United States, ranking #5043 in 2022 with 26 recorded births. The name reached its all-time peak in 2007 with 100 births ranking #2039. Since 1996, the popularity has decreased by 56.7%. In 2022, approximately 1 in every 63,029 girls born was named Brennan. FALLING Recent data shows the name is currently falling.