Rheannon is a distinctive girls' name in United States, ranking #17040 in 2008 with 6 recorded births. The name reached its all-time peak in 1999 with 20 births ranking #5384. Since 1996, the popularity has decreased by 45.5%. In 2008, approximately 1 in every 315,120 girls born was named Rheannon. FALLING Recent data shows the name is currently falling.