Iain is a distinctive boys' name in United States, ranking #4420 in 2021 with 23 recorded births. The name reached its all-time peak in 2003 with 126 births ranking #1181. Since 1996, the popularity has decreased by 73.3%. In 2021, approximately 1 in every 76,010 boys born was named Iain. FALLING Recent data shows the name is currently falling.