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).
Teagan is now well below its former popularity. All-time it's been given to 38,608 U.S. babies, the 580th most common name by sound today, peaking at 2,445 in 2016, with 1,065 in 2025.
By sound, Teagan also includes the spellings Teegan. Spellings sometimes heard the same way: Tegan.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).