Casidy is a distinctive girls' name in United States, ranking #4588 in 2001 with 26 recorded births. This places Casidy in the top 26% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2001 with 26 births ranking #4588. Since 1996, the popularity has increased by 62.5%. In 2001, approximately 1 in every 69,252 girls born was named Casidy. FALLING Recent data shows the name is currently falling.