Alfonso has been given to about 41,579 people in the United States since 1880. It was most common in 1991, which makes it a Gen X and millennial name.
Its best year was 1991, when 580 babies were given the name, ranking 395th. The typical living American called Alfonso is about 42 years old today. It is relatively most common in Texas, where it accounts for 0.02% 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.