Brennan is a distinctive boys' name in United States, ranking #719 in 2019 with 340 recorded births. The name reached its all-time peak in 2009 with 1,464 births ranking #242. Since 1996, the popularity has decreased by 62.0%. In 2019, approximately 1 in every 5,275 boys born was named Brennan. STABLE Recent data shows the name is currently stable.