Brennan is a distinctive boys' name in United States, ranking #872 in 2021 with 265 recorded births. The name reached its all-time peak in 2009 with 1,464 births ranking #242. Since 1996, the popularity has decreased by 70.4%. In 2021, approximately 1 in every 6,597 boys born was named Brennan. STABLE Recent data shows the name is currently stable.