Brennan is a distinctive boys' name in England & Wales, ranking #2079 in 2014 with 10 recorded births. The name reached its all-time peak in 2002 with 37 births ranking #559. Since 1996, the popularity has decreased by 50.0%. In 2014, approximately 1 in every 33,214 boys born was named Brennan. RISING Recent data shows the name is currently rising.