Casidy is a distinctive girls' name in United States, ranking #9915 in 2010 with 11 recorded births. The name reached its all-time peak in 2001 with 26 births ranking #4588. Since 1996, the popularity has decreased by 31.3%. In 2010, approximately 1 in every 161,575 girls born was named Casidy. FALLING Recent data shows the name is currently falling.