Ildefonso is a distinctive boys' name in United States, ranking #13067 in 2022 with 5 recorded births. The name reached its all-time peak in 1997 with 10 births ranking #5811. Since 1996, the popularity has decreased by 28.6%. In 2022, approximately 1 in every 348,875 boys born was named Ildefonso. STABLE Recent data shows the name is currently stable.