Kiernan is a distinctive girls' name in United States, ranking #4383 in 2001 with 28 recorded births. The name reached its all-time peak in 2002 with 34 births ranking #3851. Since 1996, the popularity has increased by 27.3%. In 2001, approximately 1 in every 64,306 girls born was named Kiernan. FALLING Recent data shows the name is currently falling.