Seamus has been given to about 7,809 people in the United States since 1880. It was most common in 2008, which makes it a millennial-parent name.
Its best year was 2008, when 298 babies were given the name, ranking 753rd. The typical living American called Seamus is about 19 years old today. It is relatively most common in Massachusetts, where it accounts for 0.04% 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.