Londyn carries 26,431 cumulative American girls on SSA record and currently sits at rank 305, with a 2014 peak that placed her inside the top 250. The chart is essentially a 21st-century creation: minimal use before 2008, a sharp climb across the early 2010s, a peak around 2014, and a gradual decline since then that has settled the name in the lower top 300.
The place-name source
Londyn is a modern American respelling of the place-name London, the British capital, which itself derives from a Brittonic name of disputed etymology, possibly Londinium in its Roman form. The classic place-name spelling has been used as an English given name for both boys and girls in scattered modern American records, with the simpler London form gaining traction starting in the 1990s.
The Y-spelling Londyn is essentially an early-2010s American invention, following the broader pattern of replacing -on or -en endings with -yn for stylistic distinctiveness. The same logic produced Brooklyn, Madelyn, and the elaborate spellings of Camryn and Jordyn that defined a particular slice of 2010s naming aesthetics.
The geographic-name cluster
Londyn fits inside a broader 2000s and 2010s cluster of geographic place-names used as girls' first names: Brooklyn, Paris, Sydney, and Aspen all share the same place-name-as-girl-name register. The cluster reflects a particular American cultural moment of treating cities and locations as aspirational naming markers, signaling cosmopolitanism or specific personal connections.
The Y-spelling specifically slots into the broader -yn cluster: Brooklyn, Madelyn, Adalynn, and Camryn all share the same intentionally elaborate phonetic structure. Browse the broader Celtic girl names set or compare directly with London.
The counter-reading
The Y-spelling fork is a permanent administrative issue. London (with O) is significantly more common in current American records and in dictionary-default spelling, which means Londyn's bearer will clarify her name at every introduction, every form, every prescription, for the rest of her life. Parents choosing the Y-spelling should be ready for that constant correction.
The geographic-name register also reads as distinctly 2010s and may eventually feel dated as the cohort ages. Sibling pairings work across the place-name cluster: Londyn and Brooklyn, Londyn and Paris, Londyn and Sydney. The geographic-name cohort tends to travel together as a recognizable naming family. Middle names tend traditional to balance: Londyn Rose, Londyn Grace, Londyn Jane. See current rankings at SSA rankings.