The Duchy of Cornwall is a private landed estate created by Charter in 1337 when Edward III granted it to his son and heir, Prince Edward (the Black Prince) and all his subsequent heirs. It provides each Duke with an income from its assets. The current Duke is the Heir to the Throne, HRH Prince Charles. The estate comprises primarily agricultural, commercial and residential property, in addition to which the Duchy has a portfolio of financial investments. The Duchy consists of around 52,971 hectares of land in 23 counties, mostly in the South West of England. For more details, please visit the official website for the Duchy of Cornwall. Under the Sovereign Grant Act:
a grant is to be paid to heirs to the throne who are not Dukes of Cornwall to put them in a similar financial position as if they were Dukes of Cornwall; this means that in future daughters of the monarch, as well as younger sons, could benefit
if the heir is not the Duke of Cornwall and is over 18, the heir is to receive a grant based on Duchy revenues; the Monarch (who in these circumstances becomes the Duke) receives the Duchy revenues, and the Sovereign Grant is reduced by an equal amount (so in effect, the heir would receive the Duchy income)
if the Duke of Cornwall is a minor, 90% of the revenues of the Duchy go to the monarch and the Sovereign Grant is reduced accordingly