Brennan is a distinctive girls' name in United States, ranking #6978 in 2023 with 16 recorded births. The name reached its all-time peak in 2007 with 100 births ranking #2039. Since 1996, the popularity has decreased by 73.3%. In 2023, approximately 1 in every 100,165 girls born was named Brennan. FALLING Recent data shows the name is currently falling.