Cythnia has been given to about 108 people in the United States since 1880. It was most common in 1958, which makes it a midcentury name.
Its best year was 1958, when 10 babies were given the name, ranking 3984th. The typical living American called Cythnia is about 61 years old today.
Source: US Social Security Administration, national and state name files, 2025 release. Etymology researched and written by our editors. Living-population and median-age figures are our own estimates, described in the methodology.