Cassidy is a moderately popular girls' name in United States, ranking #107 in 2000 with 3,163 recorded births. The name reached its all-time peak in 1999 with 3,395 births ranking #99. Since 1996, the popularity has increased by 11.2%. In 2000, approximately 1 in every 574 girls born was named Cassidy. STABLE Recent data shows the name is currently stable.