Brennan is a distinctive boys' name in England & Wales, ranking #2259 in 2018 with 9 recorded births. This places Brennan in the top 37% of ranked UK boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2002 with 37 births ranking #559. Since 1996, the popularity has decreased by 55.0%. In 2018, approximately 1 in every 34,733 boys born was named Brennan. RISING Recent data shows the name is currently rising.