Oonagh is a distinctive girls' name in United States, ranking #18863 in 2011 with 5 recorded births. This places Oonagh in the bottom 4% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2017 with 8 births ranking #12456. In 2011, approximately 1 in every 351,761 girls born was named Oonagh. FALLING Recent data shows the name is currently falling.