In 2025, 504 US boys were named Cassius, making it the 583rd most common boys’ name of the year, down 14 places from #569 in 2024. That is 12 fewer than the 516 boys named Cassius in 2024. Its best rank for boys was #430, reached in 1880. The most boys given the name in a single year was 607, in 2021. For comparison, it was #644 in 2015 and #3,372 in 1950.
Social Security card records list Cassius in 117 years of the 146 from 1880 to 2025, starting in 1880 with 17 babies. In all, 9,766 US babies have been given the name, 0.3% of them girls and 99.6% boys. Its busiest decade was the 2010s, with 3,643 babies named Cassius.
Over the 10 years from 2016 to 2025, 5,209 US boys were named Cassius; the busiest of those years was 2021, with 607. In 2025 that was about 1 in 3,389 of the boys in SSA’s list for the year.
Among the states, Cassius ranked highest in Maine in 2025, at #181 for boys there. It was not in the top 100 of any state. Related spellings in the SSA files include Kassius (1,197 babies since 1880). Rarer spellings such as Casius, Kasius and Kassaius are summarised on this page.