Rheannon is a distinctive girls' name in United States, ranking #7434 in 1998 with 13 recorded births. The name reached its all-time peak in 1999 with 20 births ranking #5384. Since 1996, the popularity has increased by 18.2%. In 1998, approximately 1 in every 135,915 girls born was named Rheannon. FALLING Recent data shows the name is currently falling.