Cassidy is a distinctive boys' name in United States, ranking #1826 in 1999 with 54 recorded births. The name reached its all-time peak in 1996 with 78 births ranking #1371. Since 1996, the popularity has decreased by 30.8%. In 1999, approximately 1 in every 35,557 boys born was named Cassidy. STABLE Recent data shows the name is currently stable.