Brennan is a distinctive boys' name in United States, ranking #764 in 2020 with 315 recorded births. The name reached its all-time peak in 2009 with 1,464 births ranking #242. Since 1996, the popularity has decreased by 64.8%. In 2020, approximately 1 in every 5,476 boys born was named Brennan. STABLE Recent data shows the name is currently stable.