Brennan is a distinctive boys' name in United States, ranking #534 in 2016 with 549 recorded births. The name reached its all-time peak in 2009 with 1,464 births ranking #242. Since 1996, the popularity has decreased by 38.7%. In 2016, approximately 1 in every 3,456 boys born was named Brennan. STABLE Recent data shows the name is currently stable.