Casimiro has been given to about 1,084 people in the United States since 1880. It was most common in 1921, which makes it a interwar name.
Its best year was 1921, when 28 babies were given the name, ranking 1418th. The typical living American called Casimiro is about 53 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.