Casidy is a distinctive girls' name in United States, ranking #17829 in 2009 with 5 recorded births. The name reached its all-time peak in 2001 with 26 births ranking #4588. Since 1996, the popularity has decreased by 68.8%. In 2009, approximately 1 in every 367,374 girls born was named Casidy. FALLING Recent data shows the name is currently falling.