Cassidy is a moderately popular girls' name in United States, ranking #105 in 1997 with 3,143 recorded births. The name reached its all-time peak in 1999 with 3,395 births ranking #99. Since 1996, the popularity has increased by 10.5%. In 1997, approximately 1 in every 554 girls born was named Cassidy. STABLE Recent data shows the name is currently stable.