Rhiannon ranked #2462 among U.S. baby names in 2024. Since 1974, 15,330 babies have been named Rhiannon, peaking in 1999 with 651 births. The 2000s were its biggest decade, with 4,075 births. Rhiannon is on the rise, up about 36% over the past five years. It is predominantly a girls' name.