Casidy is a distinctive girls' name in United States, ranking #8693 in 1998 with 10 recorded births. The name reached its all-time peak in 2001 with 26 births ranking #4588. Since 1996, the popularity has decreased by 37.5%. In 1998, approximately 1 in every 176,689 girls born was named Casidy. FALLING Recent data shows the name is currently falling.