Kiernan is a distinctive boys' name in United States, ranking #3409 in 2025 with 34 recorded births. The name reached its all-time peak in 2008 with 77 births ranking #1888. Since 1996, the popularity has decreased by 32.0%. In 2025, approximately 1 in every 50,238 boys born was named Kiernan. RISING Recent data shows the name is currently rising.