In 2025, 9 US girls were named Cydney, making it the 10,273rd most common girls’ name of the year, down 2,593 places from #7,680 in 2024. That is 5 fewer than the 14 girls named Cydney in 2024. Its best rank for girls was #915, reached in 1997. The most girls given the name in a single year was 227, in 1998. For comparison, it was #3,715 in 2015 and #1,503 in 1950.
Social Security card records list Cydney in 80 years of the 146 from 1880 to 2025, starting in 1942 with 5 babies. In all, 5,170 US babies have been given the name, 99.5% of them girls and 0.5% boys. Its busiest decade was the 1990s, with 1,775 babies named Cydney.
Over the 10 years from 2016 to 2025, 246 US girls were named Cydney; the busiest of those years was 2016, with 48. In 2025 that was about 1 in 178,585 of the girls in SSA’s list for the year.
Related spellings in the SSA files include Sydney (187,700 babies since 1880), Sidney (108,987 babies since 1880) and Sydnee (8,255 babies since 1880).