Brennan is a distinctive boys' name in England & Wales, ranking #1804 in 2016 with 13 recorded births. The name reached its all-time peak in 2002 with 37 births ranking #559. Since 1996, the popularity has decreased by 35.0%. In 2016, approximately 1 in every 25,533 boys born was named Brennan. RISING Recent data shows the name is currently rising.