The name Louisa ranked 810th in popularity for females of all ages in a sample of the 1990 US Census.
The Ancient Germanic name Hlutwig was Latinized into Ludovicus. The French shortened this to Clovis, and over time dropped the ''c'' and changed the ''v'' to a ''u.'' Voilá, Louis. In the opinion of the French, this was an excellent name for a king -- eighteen of them, in fact.
Somewhere in this progression, the feminine Latin form Louisa was changed by the French into Louise, and from the interplay of these names a bouquet of girls' names grew -- Eloise, Heloise, Eloisa, Luisa and others.
Louisa Catherine Johnson Adams (born 1775, died 1852)