Sinthia has been given to about 258 people in the United States since 1880. It was most common in 2000, which makes it a millennial-parent name.
Its best year was 2000, when 19 babies were given the name, ranking 5910th. The typical living American called Sinthia is about 28 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.