Kathlyn has been given to about 5,156 people in the United States since 1880. It was most common in 1951, which makes it a midcentury name.
Its best year was 1951, when 125 babies were given the name, ranking 796th. The typical living American called Kathlyn is about 58 years old today. It is relatively most common in Texas, where it accounts for 0.00% of births.
Source: US Social Security Administration, national and state name files, 2025 release, and the Office for National Statistics for England and Wales. Etymology researched and written by our editors. Living-population and median-age figures are our own estimates, described in the methodology.