Declan is a moderately popular boys' name in United States, ranking #106 in 2021 with 3,646 recorded births. The name reached its all-time peak in 2019 with 3,971 births ranking #95. Since 1996, the popularity has increased by 3,372.4%. In 2021, approximately 1 in every 479 boys born was named Declan. FALLING Recent data shows the name is currently falling.