Karsen is a modern spelling of Carson, a Scottish surname of uncertain origin, perhaps from a Norman place name, that is often loosely explained as "son of the marsh dwellers"; frontier scout Kit Carson gave it an American flavor. The K and -sen spelling followed when Carson hit the top 100 in the 2000s. Karsen entered the top 1000 in 2012 at number 998, its peak, and has drifted down to number 1928 in 2025.