Riordan is a distinctive boys' name in United States, ranking #10370 in 2020 with 7 recorded births. This places Riordan in the bottom 26% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2013 with 18 births ranking #5127. In 2020, approximately 1 in every 246,438 boys born was named Riordan. STABLE Recent data shows the name is currently stable.