Cassidy is a distinctive boys' name in United States, ranking #2354 in 2009 with 55 recorded births. The name reached its all-time peak in 1996 with 78 births ranking #1371. Since 1996, the popularity has decreased by 29.5%. In 2009, approximately 1 in every 36,060 boys born was named Cassidy. STABLE Recent data shows the name is currently stable.