Castor is a distinctive boys' name in United States, ranking #4250 in 2018 with 24 recorded births. This places Castor in the top 30% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2016 with 29 births ranking #3702. In 2018, approximately 1 in every 75,645 boys born was named Castor. RISING Recent data shows the name is currently rising.