Casimir is a distinctive boys' name in United States, ranking #3731 in 2019 with 29 recorded births. The name reached its all-time peak in 2025 with 73 births ranking #2039. Since 1996, the popularity has increased by 190.0%. In 2019, approximately 1 in every 61,840 boys born was named Casimir. RISING Recent data shows the name is currently rising.