Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Russell has been climbing in recent years. All-time it's been given to 378,098 U.S. babies, the 712th most common name by sound today, peaking at 7,728 in 1960, with 971 in 2025.
By sound, Russell also includes the spellings Russel.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).