In Britain the parallel form Alice, derived via Old French, has historically been more common than Adelaide, though this form did gain some currency in the 19th century due to the popularity of the German-born wife of King William IV, for whom the city of Adelaide in Australia was named in 1836.
It has never been very common as a given name in the English-speaking world, though it rose in popularity after the middle of the 20th century. In the United States it is frequently an African-American name. In Lithuania it may be given in honour of the Lithuanian-American aviator Steponas Darius (1896-1933), who died attempting to fly nonstop from New York to Lithuania. His surname was an Americanized form of the original Darašius.
Due to its favourable meaning, this name was popular among early Christians, being borne by many early saints and four popes. It has been used in England since the Middle Ages, though it has been more popular in continental Europe. A notable bearer was the German composer Felix Mendelssohn (1809-1847).
This is not the usual spelling in any of the Scandinavian languages (in Sweden and Denmark it is Freja and in Norway it is Frøja) but it is the common spelling of the goddess's name in English. In the 2000s it became popular in Britain.
In England, it began to be used as a given name after the Protestant Reformation. It was moderately common in the 19th century. It began to rise in popularity again in the late 1980s, probably helped along by characters on the American television shows Friends (1994-2004) and Charmed (1998-2006). It is currently much more common in the United Kingdom, Australia and New Zealand than the United States.
A moon of Saturn bears this name, in honour of the Titan.
Due to the saint's popularity, the name came into general use in medieval Europe, especially in Spain and France. It was also borne by a 16th-century king of Portugal who died in a crusade against Morocco.